1 /* SCTP kernel implementation 2 * (C) Copyright IBM Corp. 2001, 2004 3 * Copyright (c) 1999-2000 Cisco, Inc. 4 * Copyright (c) 1999-2001 Motorola, Inc. 5 * Copyright (c) 2001-2002 Intel Corp. 6 * Copyright (c) 2002 Nokia Corp. 7 * 8 * This is part of the SCTP Linux Kernel Implementation. 9 * 10 * These are the state functions for the state machine. 11 * 12 * This SCTP implementation is free software; 13 * you can redistribute it and/or modify it under the terms of 14 * the GNU General Public License as published by 15 * the Free Software Foundation; either version 2, or (at your option) 16 * any later version. 17 * 18 * This SCTP implementation is distributed in the hope that it 19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied 20 * ************************ 21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 22 * See the GNU General Public License for more details. 23 * 24 * You should have received a copy of the GNU General Public License 25 * along with GNU CC; see the file COPYING. If not, see 26 * <http://www.gnu.org/licenses/>. 27 * 28 * Please send any bug reports or fixes you make to the 29 * email address(es): 30 * lksctp developers <linux-sctp@vger.kernel.org> 31 * 32 * Written or modified by: 33 * La Monte H.P. Yarroll <piggy@acm.org> 34 * Karl Knutson <karl@athena.chicago.il.us> 35 * Mathew Kotowsky <kotowsky@sctp.org> 36 * Sridhar Samudrala <samudrala@us.ibm.com> 37 * Jon Grimm <jgrimm@us.ibm.com> 38 * Hui Huang <hui.huang@nokia.com> 39 * Dajiang Zhang <dajiang.zhang@nokia.com> 40 * Daisy Chang <daisyc@us.ibm.com> 41 * Ardelle Fan <ardelle.fan@intel.com> 42 * Ryan Layer <rmlayer@us.ibm.com> 43 * Kevin Gao <kevin.gao@intel.com> 44 */ 45 46 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 47 48 #include <linux/types.h> 49 #include <linux/kernel.h> 50 #include <linux/ip.h> 51 #include <linux/ipv6.h> 52 #include <linux/net.h> 53 #include <linux/inet.h> 54 #include <linux/slab.h> 55 #include <net/sock.h> 56 #include <net/inet_ecn.h> 57 #include <linux/skbuff.h> 58 #include <net/sctp/sctp.h> 59 #include <net/sctp/sm.h> 60 #include <net/sctp/structs.h> 61 62 static struct sctp_packet *sctp_abort_pkt_new(struct net *net, 63 const struct sctp_endpoint *ep, 64 const struct sctp_association *asoc, 65 struct sctp_chunk *chunk, 66 const void *payload, 67 size_t paylen); 68 static int sctp_eat_data(const struct sctp_association *asoc, 69 struct sctp_chunk *chunk, 70 sctp_cmd_seq_t *commands); 71 static struct sctp_packet *sctp_ootb_pkt_new(struct net *net, 72 const struct sctp_association *asoc, 73 const struct sctp_chunk *chunk); 74 static void sctp_send_stale_cookie_err(struct net *net, 75 const struct sctp_endpoint *ep, 76 const struct sctp_association *asoc, 77 const struct sctp_chunk *chunk, 78 sctp_cmd_seq_t *commands, 79 struct sctp_chunk *err_chunk); 80 static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net, 81 const struct sctp_endpoint *ep, 82 const struct sctp_association *asoc, 83 const sctp_subtype_t type, 84 void *arg, 85 sctp_cmd_seq_t *commands); 86 static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net, 87 const struct sctp_endpoint *ep, 88 const struct sctp_association *asoc, 89 const sctp_subtype_t type, 90 void *arg, 91 sctp_cmd_seq_t *commands); 92 static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net, 93 const struct sctp_endpoint *ep, 94 const struct sctp_association *asoc, 95 const sctp_subtype_t type, 96 void *arg, 97 sctp_cmd_seq_t *commands); 98 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk); 99 100 static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net, 101 sctp_cmd_seq_t *commands, 102 __be16 error, int sk_err, 103 const struct sctp_association *asoc, 104 struct sctp_transport *transport); 105 106 static sctp_disposition_t sctp_sf_abort_violation( 107 struct net *net, 108 const struct sctp_endpoint *ep, 109 const struct sctp_association *asoc, 110 void *arg, 111 sctp_cmd_seq_t *commands, 112 const __u8 *payload, 113 const size_t paylen); 114 115 static sctp_disposition_t sctp_sf_violation_chunklen( 116 struct net *net, 117 const struct sctp_endpoint *ep, 118 const struct sctp_association *asoc, 119 const sctp_subtype_t type, 120 void *arg, 121 sctp_cmd_seq_t *commands); 122 123 static sctp_disposition_t sctp_sf_violation_paramlen( 124 struct net *net, 125 const struct sctp_endpoint *ep, 126 const struct sctp_association *asoc, 127 const sctp_subtype_t type, 128 void *arg, void *ext, 129 sctp_cmd_seq_t *commands); 130 131 static sctp_disposition_t sctp_sf_violation_ctsn( 132 struct net *net, 133 const struct sctp_endpoint *ep, 134 const struct sctp_association *asoc, 135 const sctp_subtype_t type, 136 void *arg, 137 sctp_cmd_seq_t *commands); 138 139 static sctp_disposition_t sctp_sf_violation_chunk( 140 struct net *net, 141 const struct sctp_endpoint *ep, 142 const struct sctp_association *asoc, 143 const sctp_subtype_t type, 144 void *arg, 145 sctp_cmd_seq_t *commands); 146 147 static sctp_ierror_t sctp_sf_authenticate(struct net *net, 148 const struct sctp_endpoint *ep, 149 const struct sctp_association *asoc, 150 const sctp_subtype_t type, 151 struct sctp_chunk *chunk); 152 153 static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net, 154 const struct sctp_endpoint *ep, 155 const struct sctp_association *asoc, 156 const sctp_subtype_t type, 157 void *arg, 158 sctp_cmd_seq_t *commands); 159 160 /* Small helper function that checks if the chunk length 161 * is of the appropriate length. The 'required_length' argument 162 * is set to be the size of a specific chunk we are testing. 163 * Return Values: true = Valid length 164 * false = Invalid length 165 * 166 */ 167 static inline bool 168 sctp_chunk_length_valid(struct sctp_chunk *chunk, __u16 required_length) 169 { 170 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 171 172 /* Previously already marked? */ 173 if (unlikely(chunk->pdiscard)) 174 return false; 175 if (unlikely(chunk_length < required_length)) 176 return false; 177 178 return true; 179 } 180 181 /********************************************************** 182 * These are the state functions for handling chunk events. 183 **********************************************************/ 184 185 /* 186 * Process the final SHUTDOWN COMPLETE. 187 * 188 * Section: 4 (C) (diagram), 9.2 189 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 190 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 191 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 192 * should stop the T2-shutdown timer and remove all knowledge of the 193 * association (and thus the association enters the CLOSED state). 194 * 195 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 196 * C) Rules for packet carrying SHUTDOWN COMPLETE: 197 * ... 198 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 199 * if the Verification Tag field of the packet matches its own tag and 200 * the T bit is not set 201 * OR 202 * it is set to its peer's tag and the T bit is set in the Chunk 203 * Flags. 204 * Otherwise, the receiver MUST silently discard the packet 205 * and take no further action. An endpoint MUST ignore the 206 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 207 * 208 * Inputs 209 * (endpoint, asoc, chunk) 210 * 211 * Outputs 212 * (asoc, reply_msg, msg_up, timers, counters) 213 * 214 * The return value is the disposition of the chunk. 215 */ 216 sctp_disposition_t sctp_sf_do_4_C(struct net *net, 217 const struct sctp_endpoint *ep, 218 const struct sctp_association *asoc, 219 const sctp_subtype_t type, 220 void *arg, 221 sctp_cmd_seq_t *commands) 222 { 223 struct sctp_chunk *chunk = arg; 224 struct sctp_ulpevent *ev; 225 226 if (!sctp_vtag_verify_either(chunk, asoc)) 227 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 228 229 /* RFC 2960 6.10 Bundling 230 * 231 * An endpoint MUST NOT bundle INIT, INIT ACK or 232 * SHUTDOWN COMPLETE with any other chunks. 233 */ 234 if (!chunk->singleton) 235 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 236 237 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */ 238 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 239 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 240 commands); 241 242 /* RFC 2960 10.2 SCTP-to-ULP 243 * 244 * H) SHUTDOWN COMPLETE notification 245 * 246 * When SCTP completes the shutdown procedures (section 9.2) this 247 * notification is passed to the upper layer. 248 */ 249 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 250 0, 0, 0, NULL, GFP_ATOMIC); 251 if (ev) 252 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 253 SCTP_ULPEVENT(ev)); 254 255 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 256 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 257 * not the chunk should be discarded. If the endpoint is in 258 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 259 * T2-shutdown timer and remove all knowledge of the 260 * association (and thus the association enters the CLOSED 261 * state). 262 */ 263 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 264 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 265 266 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 267 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 268 269 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 270 SCTP_STATE(SCTP_STATE_CLOSED)); 271 272 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 273 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 274 275 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 276 277 return SCTP_DISPOSITION_DELETE_TCB; 278 } 279 280 /* 281 * Respond to a normal INIT chunk. 282 * We are the side that is being asked for an association. 283 * 284 * Section: 5.1 Normal Establishment of an Association, B 285 * B) "Z" shall respond immediately with an INIT ACK chunk. The 286 * destination IP address of the INIT ACK MUST be set to the source 287 * IP address of the INIT to which this INIT ACK is responding. In 288 * the response, besides filling in other parameters, "Z" must set the 289 * Verification Tag field to Tag_A, and also provide its own 290 * Verification Tag (Tag_Z) in the Initiate Tag field. 291 * 292 * Verification Tag: Must be 0. 293 * 294 * Inputs 295 * (endpoint, asoc, chunk) 296 * 297 * Outputs 298 * (asoc, reply_msg, msg_up, timers, counters) 299 * 300 * The return value is the disposition of the chunk. 301 */ 302 sctp_disposition_t sctp_sf_do_5_1B_init(struct net *net, 303 const struct sctp_endpoint *ep, 304 const struct sctp_association *asoc, 305 const sctp_subtype_t type, 306 void *arg, 307 sctp_cmd_seq_t *commands) 308 { 309 struct sctp_chunk *chunk = arg; 310 struct sctp_chunk *repl; 311 struct sctp_association *new_asoc; 312 struct sctp_chunk *err_chunk; 313 struct sctp_packet *packet; 314 sctp_unrecognized_param_t *unk_param; 315 int len; 316 317 /* 6.10 Bundling 318 * An endpoint MUST NOT bundle INIT, INIT ACK or 319 * SHUTDOWN COMPLETE with any other chunks. 320 * 321 * IG Section 2.11.2 322 * Furthermore, we require that the receiver of an INIT chunk MUST 323 * enforce these rules by silently discarding an arriving packet 324 * with an INIT chunk that is bundled with other chunks. 325 */ 326 if (!chunk->singleton) 327 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 328 329 /* If the packet is an OOTB packet which is temporarily on the 330 * control endpoint, respond with an ABORT. 331 */ 332 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 333 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 334 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 335 } 336 337 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 338 * Tag. 339 */ 340 if (chunk->sctp_hdr->vtag != 0) 341 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 342 343 /* Make sure that the INIT chunk has a valid length. 344 * Normally, this would cause an ABORT with a Protocol Violation 345 * error, but since we don't have an association, we'll 346 * just discard the packet. 347 */ 348 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 349 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 350 351 /* If the INIT is coming toward a closing socket, we'll send back 352 * and ABORT. Essentially, this catches the race of INIT being 353 * backloged to the socket at the same time as the user isses close(). 354 * Since the socket and all its associations are going away, we 355 * can treat this OOTB 356 */ 357 if (sctp_sstate(ep->base.sk, CLOSING)) 358 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 359 360 /* Verify the INIT chunk before processing it. */ 361 err_chunk = NULL; 362 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 363 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 364 &err_chunk)) { 365 /* This chunk contains fatal error. It is to be discarded. 366 * Send an ABORT, with causes if there is any. 367 */ 368 if (err_chunk) { 369 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 370 (__u8 *)(err_chunk->chunk_hdr) + 371 sizeof(struct sctp_chunkhdr), 372 ntohs(err_chunk->chunk_hdr->length) - 373 sizeof(struct sctp_chunkhdr)); 374 375 sctp_chunk_free(err_chunk); 376 377 if (packet) { 378 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 379 SCTP_PACKET(packet)); 380 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 381 return SCTP_DISPOSITION_CONSUME; 382 } else { 383 return SCTP_DISPOSITION_NOMEM; 384 } 385 } else { 386 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 387 commands); 388 } 389 } 390 391 /* Grab the INIT header. */ 392 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 393 394 /* Tag the variable length parameters. */ 395 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 396 397 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 398 if (!new_asoc) 399 goto nomem; 400 401 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 402 sctp_scope(sctp_source(chunk)), 403 GFP_ATOMIC) < 0) 404 goto nomem_init; 405 406 /* The call, sctp_process_init(), can fail on memory allocation. */ 407 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 408 (struct sctp_init_chunk *)chunk->chunk_hdr, 409 GFP_ATOMIC)) 410 goto nomem_init; 411 412 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 413 414 /* If there are errors need to be reported for unknown parameters, 415 * make sure to reserve enough room in the INIT ACK for them. 416 */ 417 len = 0; 418 if (err_chunk) 419 len = ntohs(err_chunk->chunk_hdr->length) - 420 sizeof(struct sctp_chunkhdr); 421 422 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 423 if (!repl) 424 goto nomem_init; 425 426 /* If there are errors need to be reported for unknown parameters, 427 * include them in the outgoing INIT ACK as "Unrecognized parameter" 428 * parameter. 429 */ 430 if (err_chunk) { 431 /* Get the "Unrecognized parameter" parameter(s) out of the 432 * ERROR chunk generated by sctp_verify_init(). Since the 433 * error cause code for "unknown parameter" and the 434 * "Unrecognized parameter" type is the same, we can 435 * construct the parameters in INIT ACK by copying the 436 * ERROR causes over. 437 */ 438 unk_param = (sctp_unrecognized_param_t *) 439 ((__u8 *)(err_chunk->chunk_hdr) + 440 sizeof(struct sctp_chunkhdr)); 441 /* Replace the cause code with the "Unrecognized parameter" 442 * parameter type. 443 */ 444 sctp_addto_chunk(repl, len, unk_param); 445 sctp_chunk_free(err_chunk); 446 } 447 448 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 449 450 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 451 452 /* 453 * Note: After sending out INIT ACK with the State Cookie parameter, 454 * "Z" MUST NOT allocate any resources, nor keep any states for the 455 * new association. Otherwise, "Z" will be vulnerable to resource 456 * attacks. 457 */ 458 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 459 460 return SCTP_DISPOSITION_DELETE_TCB; 461 462 nomem_init: 463 sctp_association_free(new_asoc); 464 nomem: 465 if (err_chunk) 466 sctp_chunk_free(err_chunk); 467 return SCTP_DISPOSITION_NOMEM; 468 } 469 470 /* 471 * Respond to a normal INIT ACK chunk. 472 * We are the side that is initiating the association. 473 * 474 * Section: 5.1 Normal Establishment of an Association, C 475 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 476 * timer and leave COOKIE-WAIT state. "A" shall then send the State 477 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 478 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 479 * 480 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 481 * DATA chunks, but it MUST be the first chunk in the packet and 482 * until the COOKIE ACK is returned the sender MUST NOT send any 483 * other packets to the peer. 484 * 485 * Verification Tag: 3.3.3 486 * If the value of the Initiate Tag in a received INIT ACK chunk is 487 * found to be 0, the receiver MUST treat it as an error and close the 488 * association by transmitting an ABORT. 489 * 490 * Inputs 491 * (endpoint, asoc, chunk) 492 * 493 * Outputs 494 * (asoc, reply_msg, msg_up, timers, counters) 495 * 496 * The return value is the disposition of the chunk. 497 */ 498 sctp_disposition_t sctp_sf_do_5_1C_ack(struct net *net, 499 const struct sctp_endpoint *ep, 500 const struct sctp_association *asoc, 501 const sctp_subtype_t type, 502 void *arg, 503 sctp_cmd_seq_t *commands) 504 { 505 struct sctp_chunk *chunk = arg; 506 struct sctp_init_chunk *initchunk; 507 struct sctp_chunk *err_chunk; 508 struct sctp_packet *packet; 509 510 if (!sctp_vtag_verify(chunk, asoc)) 511 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 512 513 /* 6.10 Bundling 514 * An endpoint MUST NOT bundle INIT, INIT ACK or 515 * SHUTDOWN COMPLETE with any other chunks. 516 */ 517 if (!chunk->singleton) 518 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 519 520 /* Make sure that the INIT-ACK chunk has a valid length */ 521 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t))) 522 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 523 commands); 524 /* Grab the INIT header. */ 525 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 526 527 /* Verify the INIT chunk before processing it. */ 528 err_chunk = NULL; 529 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 530 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 531 &err_chunk)) { 532 533 sctp_error_t error = SCTP_ERROR_NO_RESOURCE; 534 535 /* This chunk contains fatal error. It is to be discarded. 536 * Send an ABORT, with causes. If there are no causes, 537 * then there wasn't enough memory. Just terminate 538 * the association. 539 */ 540 if (err_chunk) { 541 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 542 (__u8 *)(err_chunk->chunk_hdr) + 543 sizeof(struct sctp_chunkhdr), 544 ntohs(err_chunk->chunk_hdr->length) - 545 sizeof(struct sctp_chunkhdr)); 546 547 sctp_chunk_free(err_chunk); 548 549 if (packet) { 550 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 551 SCTP_PACKET(packet)); 552 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 553 error = SCTP_ERROR_INV_PARAM; 554 } 555 } 556 557 /* SCTP-AUTH, Section 6.3: 558 * It should be noted that if the receiver wants to tear 559 * down an association in an authenticated way only, the 560 * handling of malformed packets should not result in 561 * tearing down the association. 562 * 563 * This means that if we only want to abort associations 564 * in an authenticated way (i.e AUTH+ABORT), then we 565 * can't destroy this association just because the packet 566 * was malformed. 567 */ 568 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 569 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 570 571 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 572 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, 573 asoc, chunk->transport); 574 } 575 576 /* Tag the variable length parameters. Note that we never 577 * convert the parameters in an INIT chunk. 578 */ 579 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 580 581 initchunk = (struct sctp_init_chunk *)chunk->chunk_hdr; 582 583 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 584 SCTP_PEER_INIT(initchunk)); 585 586 /* Reset init error count upon receipt of INIT-ACK. */ 587 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 588 589 /* 5.1 C) "A" shall stop the T1-init timer and leave 590 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 591 * timer, and enter the COOKIE-ECHOED state. 592 */ 593 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 594 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 595 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 596 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 597 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 598 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 599 600 /* SCTP-AUTH: genereate the assocition shared keys so that 601 * we can potentially signe the COOKIE-ECHO. 602 */ 603 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); 604 605 /* 5.1 C) "A" shall then send the State Cookie received in the 606 * INIT ACK chunk in a COOKIE ECHO chunk, ... 607 */ 608 /* If there is any errors to report, send the ERROR chunk generated 609 * for unknown parameters as well. 610 */ 611 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 612 SCTP_CHUNK(err_chunk)); 613 614 return SCTP_DISPOSITION_CONSUME; 615 } 616 617 /* 618 * Respond to a normal COOKIE ECHO chunk. 619 * We are the side that is being asked for an association. 620 * 621 * Section: 5.1 Normal Establishment of an Association, D 622 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 623 * with a COOKIE ACK chunk after building a TCB and moving to 624 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 625 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 626 * chunk MUST be the first chunk in the packet. 627 * 628 * IMPLEMENTATION NOTE: An implementation may choose to send the 629 * Communication Up notification to the SCTP user upon reception 630 * of a valid COOKIE ECHO chunk. 631 * 632 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 633 * D) Rules for packet carrying a COOKIE ECHO 634 * 635 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 636 * Initial Tag received in the INIT ACK. 637 * 638 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 639 * 640 * Inputs 641 * (endpoint, asoc, chunk) 642 * 643 * Outputs 644 * (asoc, reply_msg, msg_up, timers, counters) 645 * 646 * The return value is the disposition of the chunk. 647 */ 648 sctp_disposition_t sctp_sf_do_5_1D_ce(struct net *net, 649 const struct sctp_endpoint *ep, 650 const struct sctp_association *asoc, 651 const sctp_subtype_t type, void *arg, 652 sctp_cmd_seq_t *commands) 653 { 654 struct sctp_chunk *chunk = arg; 655 struct sctp_association *new_asoc; 656 struct sctp_init_chunk *peer_init; 657 struct sctp_chunk *repl; 658 struct sctp_ulpevent *ev, *ai_ev = NULL; 659 int error = 0; 660 struct sctp_chunk *err_chk_p; 661 struct sock *sk; 662 663 /* If the packet is an OOTB packet which is temporarily on the 664 * control endpoint, respond with an ABORT. 665 */ 666 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 667 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 668 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 669 } 670 671 /* Make sure that the COOKIE_ECHO chunk has a valid length. 672 * In this case, we check that we have enough for at least a 673 * chunk header. More detailed verification is done 674 * in sctp_unpack_cookie(). 675 */ 676 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 677 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 678 679 /* If the endpoint is not listening or if the number of associations 680 * on the TCP-style socket exceed the max backlog, respond with an 681 * ABORT. 682 */ 683 sk = ep->base.sk; 684 if (!sctp_sstate(sk, LISTENING) || 685 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk))) 686 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 687 688 /* "Decode" the chunk. We have no optional parameters so we 689 * are in good shape. 690 */ 691 chunk->subh.cookie_hdr = 692 (struct sctp_signed_cookie *)chunk->skb->data; 693 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 694 sizeof(struct sctp_chunkhdr))) 695 goto nomem; 696 697 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 698 * "Z" will reply with a COOKIE ACK chunk after building a TCB 699 * and moving to the ESTABLISHED state. 700 */ 701 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 702 &err_chk_p); 703 704 /* FIXME: 705 * If the re-build failed, what is the proper error path 706 * from here? 707 * 708 * [We should abort the association. --piggy] 709 */ 710 if (!new_asoc) { 711 /* FIXME: Several errors are possible. A bad cookie should 712 * be silently discarded, but think about logging it too. 713 */ 714 switch (error) { 715 case -SCTP_IERROR_NOMEM: 716 goto nomem; 717 718 case -SCTP_IERROR_STALE_COOKIE: 719 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 720 err_chk_p); 721 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 722 723 case -SCTP_IERROR_BAD_SIG: 724 default: 725 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 726 } 727 } 728 729 730 /* Delay state machine commands until later. 731 * 732 * Re-build the bind address for the association is done in 733 * the sctp_unpack_cookie() already. 734 */ 735 /* This is a brand-new association, so these are not yet side 736 * effects--it is safe to run them here. 737 */ 738 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 739 740 if (!sctp_process_init(new_asoc, chunk, 741 &chunk->subh.cookie_hdr->c.peer_addr, 742 peer_init, GFP_ATOMIC)) 743 goto nomem_init; 744 745 /* SCTP-AUTH: Now that we've populate required fields in 746 * sctp_process_init, set up the assocaition shared keys as 747 * necessary so that we can potentially authenticate the ACK 748 */ 749 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC); 750 if (error) 751 goto nomem_init; 752 753 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo 754 * is supposed to be authenticated and we have to do delayed 755 * authentication. We've just recreated the association using 756 * the information in the cookie and now it's much easier to 757 * do the authentication. 758 */ 759 if (chunk->auth_chunk) { 760 struct sctp_chunk auth; 761 sctp_ierror_t ret; 762 763 /* Make sure that we and the peer are AUTH capable */ 764 if (!net->sctp.auth_enable || !new_asoc->peer.auth_capable) { 765 sctp_association_free(new_asoc); 766 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 767 } 768 769 /* set-up our fake chunk so that we can process it */ 770 auth.skb = chunk->auth_chunk; 771 auth.asoc = chunk->asoc; 772 auth.sctp_hdr = chunk->sctp_hdr; 773 auth.chunk_hdr = (struct sctp_chunkhdr *) 774 skb_push(chunk->auth_chunk, 775 sizeof(struct sctp_chunkhdr)); 776 skb_pull(chunk->auth_chunk, sizeof(struct sctp_chunkhdr)); 777 auth.transport = chunk->transport; 778 779 ret = sctp_sf_authenticate(net, ep, new_asoc, type, &auth); 780 if (ret != SCTP_IERROR_NO_ERROR) { 781 sctp_association_free(new_asoc); 782 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 783 } 784 } 785 786 repl = sctp_make_cookie_ack(new_asoc, chunk); 787 if (!repl) 788 goto nomem_init; 789 790 /* RFC 2960 5.1 Normal Establishment of an Association 791 * 792 * D) IMPLEMENTATION NOTE: An implementation may choose to 793 * send the Communication Up notification to the SCTP user 794 * upon reception of a valid COOKIE ECHO chunk. 795 */ 796 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 797 new_asoc->c.sinit_num_ostreams, 798 new_asoc->c.sinit_max_instreams, 799 NULL, GFP_ATOMIC); 800 if (!ev) 801 goto nomem_ev; 802 803 /* Sockets API Draft Section 5.3.1.6 804 * When a peer sends a Adaptation Layer Indication parameter , SCTP 805 * delivers this notification to inform the application that of the 806 * peers requested adaptation layer. 807 */ 808 if (new_asoc->peer.adaptation_ind) { 809 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 810 GFP_ATOMIC); 811 if (!ai_ev) 812 goto nomem_aiev; 813 } 814 815 /* Add all the state machine commands now since we've created 816 * everything. This way we don't introduce memory corruptions 817 * during side-effect processing and correclty count established 818 * associations. 819 */ 820 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 821 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 822 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 823 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 824 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS); 825 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 826 827 if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 828 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 829 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 830 831 /* This will send the COOKIE ACK */ 832 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 833 834 /* Queue the ASSOC_CHANGE event */ 835 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 836 837 /* Send up the Adaptation Layer Indication event */ 838 if (ai_ev) 839 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 840 SCTP_ULPEVENT(ai_ev)); 841 842 return SCTP_DISPOSITION_CONSUME; 843 844 nomem_aiev: 845 sctp_ulpevent_free(ev); 846 nomem_ev: 847 sctp_chunk_free(repl); 848 nomem_init: 849 sctp_association_free(new_asoc); 850 nomem: 851 return SCTP_DISPOSITION_NOMEM; 852 } 853 854 /* 855 * Respond to a normal COOKIE ACK chunk. 856 * We are the side that is asking for an association. 857 * 858 * RFC 2960 5.1 Normal Establishment of an Association 859 * 860 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 861 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 862 * timer. It may also notify its ULP about the successful 863 * establishment of the association with a Communication Up 864 * notification (see Section 10). 865 * 866 * Verification Tag: 867 * Inputs 868 * (endpoint, asoc, chunk) 869 * 870 * Outputs 871 * (asoc, reply_msg, msg_up, timers, counters) 872 * 873 * The return value is the disposition of the chunk. 874 */ 875 sctp_disposition_t sctp_sf_do_5_1E_ca(struct net *net, 876 const struct sctp_endpoint *ep, 877 const struct sctp_association *asoc, 878 const sctp_subtype_t type, void *arg, 879 sctp_cmd_seq_t *commands) 880 { 881 struct sctp_chunk *chunk = arg; 882 struct sctp_ulpevent *ev; 883 884 if (!sctp_vtag_verify(chunk, asoc)) 885 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 886 887 /* Verify that the chunk length for the COOKIE-ACK is OK. 888 * If we don't do this, any bundled chunks may be junked. 889 */ 890 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 891 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 892 commands); 893 894 /* Reset init error count upon receipt of COOKIE-ACK, 895 * to avoid problems with the managemement of this 896 * counter in stale cookie situations when a transition back 897 * from the COOKIE-ECHOED state to the COOKIE-WAIT 898 * state is performed. 899 */ 900 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 901 902 /* RFC 2960 5.1 Normal Establishment of an Association 903 * 904 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 905 * from the COOKIE-ECHOED state to the ESTABLISHED state, 906 * stopping the T1-cookie timer. 907 */ 908 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 909 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 910 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 911 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 912 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 913 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS); 914 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 915 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 916 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 917 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 918 919 /* It may also notify its ULP about the successful 920 * establishment of the association with a Communication Up 921 * notification (see Section 10). 922 */ 923 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 924 0, asoc->c.sinit_num_ostreams, 925 asoc->c.sinit_max_instreams, 926 NULL, GFP_ATOMIC); 927 928 if (!ev) 929 goto nomem; 930 931 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 932 933 /* Sockets API Draft Section 5.3.1.6 934 * When a peer sends a Adaptation Layer Indication parameter , SCTP 935 * delivers this notification to inform the application that of the 936 * peers requested adaptation layer. 937 */ 938 if (asoc->peer.adaptation_ind) { 939 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 940 if (!ev) 941 goto nomem; 942 943 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 944 SCTP_ULPEVENT(ev)); 945 } 946 947 return SCTP_DISPOSITION_CONSUME; 948 nomem: 949 return SCTP_DISPOSITION_NOMEM; 950 } 951 952 /* Generate and sendout a heartbeat packet. */ 953 static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep, 954 const struct sctp_association *asoc, 955 const sctp_subtype_t type, 956 void *arg, 957 sctp_cmd_seq_t *commands) 958 { 959 struct sctp_transport *transport = (struct sctp_transport *) arg; 960 struct sctp_chunk *reply; 961 962 /* Send a heartbeat to our peer. */ 963 reply = sctp_make_heartbeat(asoc, transport); 964 if (!reply) 965 return SCTP_DISPOSITION_NOMEM; 966 967 /* Set rto_pending indicating that an RTT measurement 968 * is started with this heartbeat chunk. 969 */ 970 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 971 SCTP_TRANSPORT(transport)); 972 973 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 974 return SCTP_DISPOSITION_CONSUME; 975 } 976 977 /* Generate a HEARTBEAT packet on the given transport. */ 978 sctp_disposition_t sctp_sf_sendbeat_8_3(struct net *net, 979 const struct sctp_endpoint *ep, 980 const struct sctp_association *asoc, 981 const sctp_subtype_t type, 982 void *arg, 983 sctp_cmd_seq_t *commands) 984 { 985 struct sctp_transport *transport = (struct sctp_transport *) arg; 986 987 if (asoc->overall_error_count >= asoc->max_retrans) { 988 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 989 SCTP_ERROR(ETIMEDOUT)); 990 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 991 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 992 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 993 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 994 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 995 return SCTP_DISPOSITION_DELETE_TCB; 996 } 997 998 /* Section 3.3.5. 999 * The Sender-specific Heartbeat Info field should normally include 1000 * information about the sender's current time when this HEARTBEAT 1001 * chunk is sent and the destination transport address to which this 1002 * HEARTBEAT is sent (see Section 8.3). 1003 */ 1004 1005 if (transport->param_flags & SPP_HB_ENABLE) { 1006 if (SCTP_DISPOSITION_NOMEM == 1007 sctp_sf_heartbeat(ep, asoc, type, arg, 1008 commands)) 1009 return SCTP_DISPOSITION_NOMEM; 1010 1011 /* Set transport error counter and association error counter 1012 * when sending heartbeat. 1013 */ 1014 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 1015 SCTP_TRANSPORT(transport)); 1016 } 1017 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE, 1018 SCTP_TRANSPORT(transport)); 1019 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 1020 SCTP_TRANSPORT(transport)); 1021 1022 return SCTP_DISPOSITION_CONSUME; 1023 } 1024 1025 /* resend asoc strreset_chunk. */ 1026 sctp_disposition_t sctp_sf_send_reconf(struct net *net, 1027 const struct sctp_endpoint *ep, 1028 const struct sctp_association *asoc, 1029 const sctp_subtype_t type, void *arg, 1030 sctp_cmd_seq_t *commands) 1031 { 1032 struct sctp_transport *transport = arg; 1033 1034 if (asoc->overall_error_count >= asoc->max_retrans) { 1035 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 1036 SCTP_ERROR(ETIMEDOUT)); 1037 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 1038 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 1039 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 1040 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1041 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1042 return SCTP_DISPOSITION_DELETE_TCB; 1043 } 1044 1045 sctp_chunk_hold(asoc->strreset_chunk); 1046 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1047 SCTP_CHUNK(asoc->strreset_chunk)); 1048 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 1049 1050 return SCTP_DISPOSITION_CONSUME; 1051 } 1052 1053 /* 1054 * Process an heartbeat request. 1055 * 1056 * Section: 8.3 Path Heartbeat 1057 * The receiver of the HEARTBEAT should immediately respond with a 1058 * HEARTBEAT ACK that contains the Heartbeat Information field copied 1059 * from the received HEARTBEAT chunk. 1060 * 1061 * Verification Tag: 8.5 Verification Tag [Normal verification] 1062 * When receiving an SCTP packet, the endpoint MUST ensure that the 1063 * value in the Verification Tag field of the received SCTP packet 1064 * matches its own Tag. If the received Verification Tag value does not 1065 * match the receiver's own tag value, the receiver shall silently 1066 * discard the packet and shall not process it any further except for 1067 * those cases listed in Section 8.5.1 below. 1068 * 1069 * Inputs 1070 * (endpoint, asoc, chunk) 1071 * 1072 * Outputs 1073 * (asoc, reply_msg, msg_up, timers, counters) 1074 * 1075 * The return value is the disposition of the chunk. 1076 */ 1077 sctp_disposition_t sctp_sf_beat_8_3(struct net *net, 1078 const struct sctp_endpoint *ep, 1079 const struct sctp_association *asoc, 1080 const sctp_subtype_t type, 1081 void *arg, 1082 sctp_cmd_seq_t *commands) 1083 { 1084 struct sctp_paramhdr *param_hdr; 1085 struct sctp_chunk *chunk = arg; 1086 struct sctp_chunk *reply; 1087 size_t paylen = 0; 1088 1089 if (!sctp_vtag_verify(chunk, asoc)) 1090 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1091 1092 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1093 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) 1094 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1095 commands); 1096 1097 /* 8.3 The receiver of the HEARTBEAT should immediately 1098 * respond with a HEARTBEAT ACK that contains the Heartbeat 1099 * Information field copied from the received HEARTBEAT chunk. 1100 */ 1101 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *)chunk->skb->data; 1102 param_hdr = (struct sctp_paramhdr *)chunk->subh.hb_hdr; 1103 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(struct sctp_chunkhdr); 1104 1105 if (ntohs(param_hdr->length) > paylen) 1106 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 1107 param_hdr, commands); 1108 1109 if (!pskb_pull(chunk->skb, paylen)) 1110 goto nomem; 1111 1112 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen); 1113 if (!reply) 1114 goto nomem; 1115 1116 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1117 return SCTP_DISPOSITION_CONSUME; 1118 1119 nomem: 1120 return SCTP_DISPOSITION_NOMEM; 1121 } 1122 1123 /* 1124 * Process the returning HEARTBEAT ACK. 1125 * 1126 * Section: 8.3 Path Heartbeat 1127 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1128 * should clear the error counter of the destination transport 1129 * address to which the HEARTBEAT was sent, and mark the destination 1130 * transport address as active if it is not so marked. The endpoint may 1131 * optionally report to the upper layer when an inactive destination 1132 * address is marked as active due to the reception of the latest 1133 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1134 * clear the association overall error count as well (as defined 1135 * in section 8.1). 1136 * 1137 * The receiver of the HEARTBEAT ACK should also perform an RTT 1138 * measurement for that destination transport address using the time 1139 * value carried in the HEARTBEAT ACK chunk. 1140 * 1141 * Verification Tag: 8.5 Verification Tag [Normal verification] 1142 * 1143 * Inputs 1144 * (endpoint, asoc, chunk) 1145 * 1146 * Outputs 1147 * (asoc, reply_msg, msg_up, timers, counters) 1148 * 1149 * The return value is the disposition of the chunk. 1150 */ 1151 sctp_disposition_t sctp_sf_backbeat_8_3(struct net *net, 1152 const struct sctp_endpoint *ep, 1153 const struct sctp_association *asoc, 1154 const sctp_subtype_t type, 1155 void *arg, 1156 sctp_cmd_seq_t *commands) 1157 { 1158 struct sctp_chunk *chunk = arg; 1159 union sctp_addr from_addr; 1160 struct sctp_transport *link; 1161 sctp_sender_hb_info_t *hbinfo; 1162 unsigned long max_interval; 1163 1164 if (!sctp_vtag_verify(chunk, asoc)) 1165 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1166 1167 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1168 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr) + 1169 sizeof(sctp_sender_hb_info_t))) 1170 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1171 commands); 1172 1173 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data; 1174 /* Make sure that the length of the parameter is what we expect */ 1175 if (ntohs(hbinfo->param_hdr.length) != 1176 sizeof(sctp_sender_hb_info_t)) { 1177 return SCTP_DISPOSITION_DISCARD; 1178 } 1179 1180 from_addr = hbinfo->daddr; 1181 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1182 1183 /* This should never happen, but lets log it if so. */ 1184 if (unlikely(!link)) { 1185 if (from_addr.sa.sa_family == AF_INET6) { 1186 net_warn_ratelimited("%s association %p could not find address %pI6\n", 1187 __func__, 1188 asoc, 1189 &from_addr.v6.sin6_addr); 1190 } else { 1191 net_warn_ratelimited("%s association %p could not find address %pI4\n", 1192 __func__, 1193 asoc, 1194 &from_addr.v4.sin_addr.s_addr); 1195 } 1196 return SCTP_DISPOSITION_DISCARD; 1197 } 1198 1199 /* Validate the 64-bit random nonce. */ 1200 if (hbinfo->hb_nonce != link->hb_nonce) 1201 return SCTP_DISPOSITION_DISCARD; 1202 1203 max_interval = link->hbinterval + link->rto; 1204 1205 /* Check if the timestamp looks valid. */ 1206 if (time_after(hbinfo->sent_at, jiffies) || 1207 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1208 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received " 1209 "for transport:%p\n", __func__, link); 1210 1211 return SCTP_DISPOSITION_DISCARD; 1212 } 1213 1214 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1215 * the HEARTBEAT should clear the error counter of the 1216 * destination transport address to which the HEARTBEAT was 1217 * sent and mark the destination transport address as active if 1218 * it is not so marked. 1219 */ 1220 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1221 1222 return SCTP_DISPOSITION_CONSUME; 1223 } 1224 1225 /* Helper function to send out an abort for the restart 1226 * condition. 1227 */ 1228 static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa, 1229 struct sctp_chunk *init, 1230 sctp_cmd_seq_t *commands) 1231 { 1232 int len; 1233 struct sctp_packet *pkt; 1234 union sctp_addr_param *addrparm; 1235 struct sctp_errhdr *errhdr; 1236 struct sctp_endpoint *ep; 1237 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)]; 1238 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1239 1240 /* Build the error on the stack. We are way to malloc crazy 1241 * throughout the code today. 1242 */ 1243 errhdr = (struct sctp_errhdr *)buffer; 1244 addrparm = (union sctp_addr_param *)errhdr->variable; 1245 1246 /* Copy into a parm format. */ 1247 len = af->to_addr_param(ssa, addrparm); 1248 len += sizeof(sctp_errhdr_t); 1249 1250 errhdr->cause = SCTP_ERROR_RESTART; 1251 errhdr->length = htons(len); 1252 1253 /* Assign to the control socket. */ 1254 ep = sctp_sk(net->sctp.ctl_sock)->ep; 1255 1256 /* Association is NULL since this may be a restart attack and we 1257 * want to send back the attacker's vtag. 1258 */ 1259 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len); 1260 1261 if (!pkt) 1262 goto out; 1263 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1264 1265 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1266 1267 /* Discard the rest of the inbound packet. */ 1268 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1269 1270 out: 1271 /* Even if there is no memory, treat as a failure so 1272 * the packet will get dropped. 1273 */ 1274 return 0; 1275 } 1276 1277 static bool list_has_sctp_addr(const struct list_head *list, 1278 union sctp_addr *ipaddr) 1279 { 1280 struct sctp_transport *addr; 1281 1282 list_for_each_entry(addr, list, transports) { 1283 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr)) 1284 return true; 1285 } 1286 1287 return false; 1288 } 1289 /* A restart is occurring, check to make sure no new addresses 1290 * are being added as we may be under a takeover attack. 1291 */ 1292 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1293 const struct sctp_association *asoc, 1294 struct sctp_chunk *init, 1295 sctp_cmd_seq_t *commands) 1296 { 1297 struct net *net = sock_net(new_asoc->base.sk); 1298 struct sctp_transport *new_addr; 1299 int ret = 1; 1300 1301 /* Implementor's Guide - Section 5.2.2 1302 * ... 1303 * Before responding the endpoint MUST check to see if the 1304 * unexpected INIT adds new addresses to the association. If new 1305 * addresses are added to the association, the endpoint MUST respond 1306 * with an ABORT.. 1307 */ 1308 1309 /* Search through all current addresses and make sure 1310 * we aren't adding any new ones. 1311 */ 1312 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list, 1313 transports) { 1314 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list, 1315 &new_addr->ipaddr)) { 1316 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init, 1317 commands); 1318 ret = 0; 1319 break; 1320 } 1321 } 1322 1323 /* Return success if all addresses were found. */ 1324 return ret; 1325 } 1326 1327 /* Populate the verification/tie tags based on overlapping INIT 1328 * scenario. 1329 * 1330 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1331 */ 1332 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1333 const struct sctp_association *asoc) 1334 { 1335 switch (asoc->state) { 1336 1337 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1338 1339 case SCTP_STATE_COOKIE_WAIT: 1340 new_asoc->c.my_vtag = asoc->c.my_vtag; 1341 new_asoc->c.my_ttag = asoc->c.my_vtag; 1342 new_asoc->c.peer_ttag = 0; 1343 break; 1344 1345 case SCTP_STATE_COOKIE_ECHOED: 1346 new_asoc->c.my_vtag = asoc->c.my_vtag; 1347 new_asoc->c.my_ttag = asoc->c.my_vtag; 1348 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1349 break; 1350 1351 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1352 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1353 */ 1354 default: 1355 new_asoc->c.my_ttag = asoc->c.my_vtag; 1356 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1357 break; 1358 } 1359 1360 /* Other parameters for the endpoint SHOULD be copied from the 1361 * existing parameters of the association (e.g. number of 1362 * outbound streams) into the INIT ACK and cookie. 1363 */ 1364 new_asoc->rwnd = asoc->rwnd; 1365 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1366 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1367 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1368 } 1369 1370 /* 1371 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1372 * handling action. 1373 * 1374 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1375 * 1376 * Returns value representing action to be taken. These action values 1377 * correspond to Action/Description values in RFC 2960, Table 2. 1378 */ 1379 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1380 const struct sctp_association *asoc) 1381 { 1382 /* In this case, the peer may have restarted. */ 1383 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1384 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1385 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1386 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1387 return 'A'; 1388 1389 /* Collision case B. */ 1390 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1391 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1392 (0 == asoc->c.peer_vtag))) { 1393 return 'B'; 1394 } 1395 1396 /* Collision case D. */ 1397 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1398 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1399 return 'D'; 1400 1401 /* Collision case C. */ 1402 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1403 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1404 (0 == new_asoc->c.my_ttag) && 1405 (0 == new_asoc->c.peer_ttag)) 1406 return 'C'; 1407 1408 /* No match to any of the special cases; discard this packet. */ 1409 return 'E'; 1410 } 1411 1412 /* Common helper routine for both duplicate and simulataneous INIT 1413 * chunk handling. 1414 */ 1415 static sctp_disposition_t sctp_sf_do_unexpected_init( 1416 struct net *net, 1417 const struct sctp_endpoint *ep, 1418 const struct sctp_association *asoc, 1419 const sctp_subtype_t type, 1420 void *arg, sctp_cmd_seq_t *commands) 1421 { 1422 sctp_disposition_t retval; 1423 struct sctp_chunk *chunk = arg; 1424 struct sctp_chunk *repl; 1425 struct sctp_association *new_asoc; 1426 struct sctp_chunk *err_chunk; 1427 struct sctp_packet *packet; 1428 sctp_unrecognized_param_t *unk_param; 1429 int len; 1430 1431 /* 6.10 Bundling 1432 * An endpoint MUST NOT bundle INIT, INIT ACK or 1433 * SHUTDOWN COMPLETE with any other chunks. 1434 * 1435 * IG Section 2.11.2 1436 * Furthermore, we require that the receiver of an INIT chunk MUST 1437 * enforce these rules by silently discarding an arriving packet 1438 * with an INIT chunk that is bundled with other chunks. 1439 */ 1440 if (!chunk->singleton) 1441 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1442 1443 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1444 * Tag. 1445 */ 1446 if (chunk->sctp_hdr->vtag != 0) 1447 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 1448 1449 /* Make sure that the INIT chunk has a valid length. 1450 * In this case, we generate a protocol violation since we have 1451 * an association established. 1452 */ 1453 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 1454 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1455 commands); 1456 /* Grab the INIT header. */ 1457 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 1458 1459 /* Tag the variable length parameters. */ 1460 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 1461 1462 /* Verify the INIT chunk before processing it. */ 1463 err_chunk = NULL; 1464 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 1465 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 1466 &err_chunk)) { 1467 /* This chunk contains fatal error. It is to be discarded. 1468 * Send an ABORT, with causes if there is any. 1469 */ 1470 if (err_chunk) { 1471 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 1472 (__u8 *)(err_chunk->chunk_hdr) + 1473 sizeof(struct sctp_chunkhdr), 1474 ntohs(err_chunk->chunk_hdr->length) - 1475 sizeof(struct sctp_chunkhdr)); 1476 1477 if (packet) { 1478 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1479 SCTP_PACKET(packet)); 1480 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1481 retval = SCTP_DISPOSITION_CONSUME; 1482 } else { 1483 retval = SCTP_DISPOSITION_NOMEM; 1484 } 1485 goto cleanup; 1486 } else { 1487 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 1488 commands); 1489 } 1490 } 1491 1492 /* 1493 * Other parameters for the endpoint SHOULD be copied from the 1494 * existing parameters of the association (e.g. number of 1495 * outbound streams) into the INIT ACK and cookie. 1496 * FIXME: We are copying parameters from the endpoint not the 1497 * association. 1498 */ 1499 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1500 if (!new_asoc) 1501 goto nomem; 1502 1503 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 1504 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0) 1505 goto nomem; 1506 1507 /* In the outbound INIT ACK the endpoint MUST copy its current 1508 * Verification Tag and Peers Verification tag into a reserved 1509 * place (local tie-tag and per tie-tag) within the state cookie. 1510 */ 1511 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 1512 (struct sctp_init_chunk *)chunk->chunk_hdr, 1513 GFP_ATOMIC)) 1514 goto nomem; 1515 1516 /* Make sure no new addresses are being added during the 1517 * restart. Do not do this check for COOKIE-WAIT state, 1518 * since there are no peer addresses to check against. 1519 * Upon return an ABORT will have been sent if needed. 1520 */ 1521 if (!sctp_state(asoc, COOKIE_WAIT)) { 1522 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1523 commands)) { 1524 retval = SCTP_DISPOSITION_CONSUME; 1525 goto nomem_retval; 1526 } 1527 } 1528 1529 sctp_tietags_populate(new_asoc, asoc); 1530 1531 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1532 1533 /* If there are errors need to be reported for unknown parameters, 1534 * make sure to reserve enough room in the INIT ACK for them. 1535 */ 1536 len = 0; 1537 if (err_chunk) { 1538 len = ntohs(err_chunk->chunk_hdr->length) - 1539 sizeof(struct sctp_chunkhdr); 1540 } 1541 1542 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1543 if (!repl) 1544 goto nomem; 1545 1546 /* If there are errors need to be reported for unknown parameters, 1547 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1548 * parameter. 1549 */ 1550 if (err_chunk) { 1551 /* Get the "Unrecognized parameter" parameter(s) out of the 1552 * ERROR chunk generated by sctp_verify_init(). Since the 1553 * error cause code for "unknown parameter" and the 1554 * "Unrecognized parameter" type is the same, we can 1555 * construct the parameters in INIT ACK by copying the 1556 * ERROR causes over. 1557 */ 1558 unk_param = (sctp_unrecognized_param_t *) 1559 ((__u8 *)(err_chunk->chunk_hdr) + 1560 sizeof(struct sctp_chunkhdr)); 1561 /* Replace the cause code with the "Unrecognized parameter" 1562 * parameter type. 1563 */ 1564 sctp_addto_chunk(repl, len, unk_param); 1565 } 1566 1567 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1568 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1569 1570 /* 1571 * Note: After sending out INIT ACK with the State Cookie parameter, 1572 * "Z" MUST NOT allocate any resources for this new association. 1573 * Otherwise, "Z" will be vulnerable to resource attacks. 1574 */ 1575 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1576 retval = SCTP_DISPOSITION_CONSUME; 1577 1578 return retval; 1579 1580 nomem: 1581 retval = SCTP_DISPOSITION_NOMEM; 1582 nomem_retval: 1583 if (new_asoc) 1584 sctp_association_free(new_asoc); 1585 cleanup: 1586 if (err_chunk) 1587 sctp_chunk_free(err_chunk); 1588 return retval; 1589 } 1590 1591 /* 1592 * Handle simultaneous INIT. 1593 * This means we started an INIT and then we got an INIT request from 1594 * our peer. 1595 * 1596 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1597 * This usually indicates an initialization collision, i.e., each 1598 * endpoint is attempting, at about the same time, to establish an 1599 * association with the other endpoint. 1600 * 1601 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1602 * endpoint MUST respond with an INIT ACK using the same parameters it 1603 * sent in its original INIT chunk (including its Verification Tag, 1604 * unchanged). These original parameters are combined with those from the 1605 * newly received INIT chunk. The endpoint shall also generate a State 1606 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1607 * INIT to calculate the State Cookie. 1608 * 1609 * After that, the endpoint MUST NOT change its state, the T1-init 1610 * timer shall be left running and the corresponding TCB MUST NOT be 1611 * destroyed. The normal procedures for handling State Cookies when 1612 * a TCB exists will resolve the duplicate INITs to a single association. 1613 * 1614 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1615 * its Tie-Tags with the Tag information of itself and its peer (see 1616 * section 5.2.2 for a description of the Tie-Tags). 1617 * 1618 * Verification Tag: Not explicit, but an INIT can not have a valid 1619 * verification tag, so we skip the check. 1620 * 1621 * Inputs 1622 * (endpoint, asoc, chunk) 1623 * 1624 * Outputs 1625 * (asoc, reply_msg, msg_up, timers, counters) 1626 * 1627 * The return value is the disposition of the chunk. 1628 */ 1629 sctp_disposition_t sctp_sf_do_5_2_1_siminit(struct net *net, 1630 const struct sctp_endpoint *ep, 1631 const struct sctp_association *asoc, 1632 const sctp_subtype_t type, 1633 void *arg, 1634 sctp_cmd_seq_t *commands) 1635 { 1636 /* Call helper to do the real work for both simulataneous and 1637 * duplicate INIT chunk handling. 1638 */ 1639 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1640 } 1641 1642 /* 1643 * Handle duplicated INIT messages. These are usually delayed 1644 * restransmissions. 1645 * 1646 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1647 * COOKIE-ECHOED and COOKIE-WAIT 1648 * 1649 * Unless otherwise stated, upon reception of an unexpected INIT for 1650 * this association, the endpoint shall generate an INIT ACK with a 1651 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1652 * current Verification Tag and peer's Verification Tag into a reserved 1653 * place within the state cookie. We shall refer to these locations as 1654 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1655 * containing this INIT ACK MUST carry a Verification Tag value equal to 1656 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1657 * MUST contain a new Initiation Tag (randomly generated see Section 1658 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1659 * existing parameters of the association (e.g. number of outbound 1660 * streams) into the INIT ACK and cookie. 1661 * 1662 * After sending out the INIT ACK, the endpoint shall take no further 1663 * actions, i.e., the existing association, including its current state, 1664 * and the corresponding TCB MUST NOT be changed. 1665 * 1666 * Note: Only when a TCB exists and the association is not in a COOKIE- 1667 * WAIT state are the Tie-Tags populated. For a normal association INIT 1668 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1669 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1670 * State Cookie are populated as specified in section 5.2.1. 1671 * 1672 * Verification Tag: Not specified, but an INIT has no way of knowing 1673 * what the verification tag could be, so we ignore it. 1674 * 1675 * Inputs 1676 * (endpoint, asoc, chunk) 1677 * 1678 * Outputs 1679 * (asoc, reply_msg, msg_up, timers, counters) 1680 * 1681 * The return value is the disposition of the chunk. 1682 */ 1683 sctp_disposition_t sctp_sf_do_5_2_2_dupinit(struct net *net, 1684 const struct sctp_endpoint *ep, 1685 const struct sctp_association *asoc, 1686 const sctp_subtype_t type, 1687 void *arg, 1688 sctp_cmd_seq_t *commands) 1689 { 1690 /* Call helper to do the real work for both simulataneous and 1691 * duplicate INIT chunk handling. 1692 */ 1693 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1694 } 1695 1696 1697 /* 1698 * Unexpected INIT-ACK handler. 1699 * 1700 * Section 5.2.3 1701 * If an INIT ACK received by an endpoint in any state other than the 1702 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1703 * An unexpected INIT ACK usually indicates the processing of an old or 1704 * duplicated INIT chunk. 1705 */ 1706 sctp_disposition_t sctp_sf_do_5_2_3_initack(struct net *net, 1707 const struct sctp_endpoint *ep, 1708 const struct sctp_association *asoc, 1709 const sctp_subtype_t type, 1710 void *arg, sctp_cmd_seq_t *commands) 1711 { 1712 /* Per the above section, we'll discard the chunk if we have an 1713 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1714 */ 1715 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) 1716 return sctp_sf_ootb(net, ep, asoc, type, arg, commands); 1717 else 1718 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 1719 } 1720 1721 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1722 * 1723 * Section 5.2.4 1724 * A) In this case, the peer may have restarted. 1725 */ 1726 static sctp_disposition_t sctp_sf_do_dupcook_a(struct net *net, 1727 const struct sctp_endpoint *ep, 1728 const struct sctp_association *asoc, 1729 struct sctp_chunk *chunk, 1730 sctp_cmd_seq_t *commands, 1731 struct sctp_association *new_asoc) 1732 { 1733 struct sctp_init_chunk *peer_init; 1734 struct sctp_ulpevent *ev; 1735 struct sctp_chunk *repl; 1736 struct sctp_chunk *err; 1737 sctp_disposition_t disposition; 1738 1739 /* new_asoc is a brand-new association, so these are not yet 1740 * side effects--it is safe to run them here. 1741 */ 1742 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1743 1744 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1745 GFP_ATOMIC)) 1746 goto nomem; 1747 1748 /* Make sure no new addresses are being added during the 1749 * restart. Though this is a pretty complicated attack 1750 * since you'd have to get inside the cookie. 1751 */ 1752 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { 1753 return SCTP_DISPOSITION_CONSUME; 1754 } 1755 1756 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1757 * the peer has restarted (Action A), it MUST NOT setup a new 1758 * association but instead resend the SHUTDOWN ACK and send an ERROR 1759 * chunk with a "Cookie Received while Shutting Down" error cause to 1760 * its peer. 1761 */ 1762 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1763 disposition = sctp_sf_do_9_2_reshutack(net, ep, asoc, 1764 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1765 chunk, commands); 1766 if (SCTP_DISPOSITION_NOMEM == disposition) 1767 goto nomem; 1768 1769 err = sctp_make_op_error(asoc, chunk, 1770 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1771 NULL, 0, 0); 1772 if (err) 1773 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1774 SCTP_CHUNK(err)); 1775 1776 return SCTP_DISPOSITION_CONSUME; 1777 } 1778 1779 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked 1780 * data. Consider the optional choice of resending of this data. 1781 */ 1782 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 1783 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1784 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 1785 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1786 1787 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue 1788 * and ASCONF-ACK cache. 1789 */ 1790 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1791 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 1792 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL()); 1793 1794 repl = sctp_make_cookie_ack(new_asoc, chunk); 1795 if (!repl) 1796 goto nomem; 1797 1798 /* Report association restart to upper layer. */ 1799 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1800 new_asoc->c.sinit_num_ostreams, 1801 new_asoc->c.sinit_max_instreams, 1802 NULL, GFP_ATOMIC); 1803 if (!ev) 1804 goto nomem_ev; 1805 1806 /* Update the content of current association. */ 1807 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1808 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1809 if (sctp_state(asoc, SHUTDOWN_PENDING) && 1810 (sctp_sstate(asoc->base.sk, CLOSING) || 1811 sock_flag(asoc->base.sk, SOCK_DEAD))) { 1812 /* if were currently in SHUTDOWN_PENDING, but the socket 1813 * has been closed by user, don't transition to ESTABLISHED. 1814 * Instead trigger SHUTDOWN bundled with COOKIE_ACK. 1815 */ 1816 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1817 return sctp_sf_do_9_2_start_shutdown(net, ep, asoc, 1818 SCTP_ST_CHUNK(0), NULL, 1819 commands); 1820 } else { 1821 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1822 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1823 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1824 } 1825 return SCTP_DISPOSITION_CONSUME; 1826 1827 nomem_ev: 1828 sctp_chunk_free(repl); 1829 nomem: 1830 return SCTP_DISPOSITION_NOMEM; 1831 } 1832 1833 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1834 * 1835 * Section 5.2.4 1836 * B) In this case, both sides may be attempting to start an association 1837 * at about the same time but the peer endpoint started its INIT 1838 * after responding to the local endpoint's INIT 1839 */ 1840 /* This case represents an initialization collision. */ 1841 static sctp_disposition_t sctp_sf_do_dupcook_b(struct net *net, 1842 const struct sctp_endpoint *ep, 1843 const struct sctp_association *asoc, 1844 struct sctp_chunk *chunk, 1845 sctp_cmd_seq_t *commands, 1846 struct sctp_association *new_asoc) 1847 { 1848 struct sctp_init_chunk *peer_init; 1849 struct sctp_chunk *repl; 1850 1851 /* new_asoc is a brand-new association, so these are not yet 1852 * side effects--it is safe to run them here. 1853 */ 1854 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1855 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1856 GFP_ATOMIC)) 1857 goto nomem; 1858 1859 /* Update the content of current association. */ 1860 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1861 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1862 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1863 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1864 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1865 1866 repl = sctp_make_cookie_ack(new_asoc, chunk); 1867 if (!repl) 1868 goto nomem; 1869 1870 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1871 1872 /* RFC 2960 5.1 Normal Establishment of an Association 1873 * 1874 * D) IMPLEMENTATION NOTE: An implementation may choose to 1875 * send the Communication Up notification to the SCTP user 1876 * upon reception of a valid COOKIE ECHO chunk. 1877 * 1878 * Sadly, this needs to be implemented as a side-effect, because 1879 * we are not guaranteed to have set the association id of the real 1880 * association and so these notifications need to be delayed until 1881 * the association id is allocated. 1882 */ 1883 1884 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 1885 1886 /* Sockets API Draft Section 5.3.1.6 1887 * When a peer sends a Adaptation Layer Indication parameter , SCTP 1888 * delivers this notification to inform the application that of the 1889 * peers requested adaptation layer. 1890 * 1891 * This also needs to be done as a side effect for the same reason as 1892 * above. 1893 */ 1894 if (asoc->peer.adaptation_ind) 1895 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 1896 1897 return SCTP_DISPOSITION_CONSUME; 1898 1899 nomem: 1900 return SCTP_DISPOSITION_NOMEM; 1901 } 1902 1903 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 1904 * 1905 * Section 5.2.4 1906 * C) In this case, the local endpoint's cookie has arrived late. 1907 * Before it arrived, the local endpoint sent an INIT and received an 1908 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 1909 * but a new tag of its own. 1910 */ 1911 /* This case represents an initialization collision. */ 1912 static sctp_disposition_t sctp_sf_do_dupcook_c(struct net *net, 1913 const struct sctp_endpoint *ep, 1914 const struct sctp_association *asoc, 1915 struct sctp_chunk *chunk, 1916 sctp_cmd_seq_t *commands, 1917 struct sctp_association *new_asoc) 1918 { 1919 /* The cookie should be silently discarded. 1920 * The endpoint SHOULD NOT change states and should leave 1921 * any timers running. 1922 */ 1923 return SCTP_DISPOSITION_DISCARD; 1924 } 1925 1926 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 1927 * 1928 * Section 5.2.4 1929 * 1930 * D) When both local and remote tags match the endpoint should always 1931 * enter the ESTABLISHED state, if it has not already done so. 1932 */ 1933 /* This case represents an initialization collision. */ 1934 static sctp_disposition_t sctp_sf_do_dupcook_d(struct net *net, 1935 const struct sctp_endpoint *ep, 1936 const struct sctp_association *asoc, 1937 struct sctp_chunk *chunk, 1938 sctp_cmd_seq_t *commands, 1939 struct sctp_association *new_asoc) 1940 { 1941 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL; 1942 struct sctp_chunk *repl; 1943 1944 /* Clarification from Implementor's Guide: 1945 * D) When both local and remote tags match the endpoint should 1946 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 1947 * It should stop any cookie timer that may be running and send 1948 * a COOKIE ACK. 1949 */ 1950 1951 /* Don't accidentally move back into established state. */ 1952 if (asoc->state < SCTP_STATE_ESTABLISHED) { 1953 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1954 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 1955 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1956 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1957 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1958 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 1959 SCTP_NULL()); 1960 1961 /* RFC 2960 5.1 Normal Establishment of an Association 1962 * 1963 * D) IMPLEMENTATION NOTE: An implementation may choose 1964 * to send the Communication Up notification to the 1965 * SCTP user upon reception of a valid COOKIE 1966 * ECHO chunk. 1967 */ 1968 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 1969 SCTP_COMM_UP, 0, 1970 asoc->c.sinit_num_ostreams, 1971 asoc->c.sinit_max_instreams, 1972 NULL, GFP_ATOMIC); 1973 if (!ev) 1974 goto nomem; 1975 1976 /* Sockets API Draft Section 5.3.1.6 1977 * When a peer sends a Adaptation Layer Indication parameter, 1978 * SCTP delivers this notification to inform the application 1979 * that of the peers requested adaptation layer. 1980 */ 1981 if (asoc->peer.adaptation_ind) { 1982 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 1983 GFP_ATOMIC); 1984 if (!ai_ev) 1985 goto nomem; 1986 1987 } 1988 } 1989 1990 repl = sctp_make_cookie_ack(new_asoc, chunk); 1991 if (!repl) 1992 goto nomem; 1993 1994 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1995 1996 if (ev) 1997 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1998 SCTP_ULPEVENT(ev)); 1999 if (ai_ev) 2000 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2001 SCTP_ULPEVENT(ai_ev)); 2002 2003 return SCTP_DISPOSITION_CONSUME; 2004 2005 nomem: 2006 if (ai_ev) 2007 sctp_ulpevent_free(ai_ev); 2008 if (ev) 2009 sctp_ulpevent_free(ev); 2010 return SCTP_DISPOSITION_NOMEM; 2011 } 2012 2013 /* 2014 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 2015 * chunk was retransmitted and then delayed in the network. 2016 * 2017 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 2018 * 2019 * Verification Tag: None. Do cookie validation. 2020 * 2021 * Inputs 2022 * (endpoint, asoc, chunk) 2023 * 2024 * Outputs 2025 * (asoc, reply_msg, msg_up, timers, counters) 2026 * 2027 * The return value is the disposition of the chunk. 2028 */ 2029 sctp_disposition_t sctp_sf_do_5_2_4_dupcook(struct net *net, 2030 const struct sctp_endpoint *ep, 2031 const struct sctp_association *asoc, 2032 const sctp_subtype_t type, 2033 void *arg, 2034 sctp_cmd_seq_t *commands) 2035 { 2036 sctp_disposition_t retval; 2037 struct sctp_chunk *chunk = arg; 2038 struct sctp_association *new_asoc; 2039 int error = 0; 2040 char action; 2041 struct sctp_chunk *err_chk_p; 2042 2043 /* Make sure that the chunk has a valid length from the protocol 2044 * perspective. In this case check to make sure we have at least 2045 * enough for the chunk header. Cookie length verification is 2046 * done later. 2047 */ 2048 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 2049 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2050 commands); 2051 2052 /* "Decode" the chunk. We have no optional parameters so we 2053 * are in good shape. 2054 */ 2055 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 2056 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 2057 sizeof(struct sctp_chunkhdr))) 2058 goto nomem; 2059 2060 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 2061 * of a duplicate COOKIE ECHO match the Verification Tags of the 2062 * current association, consider the State Cookie valid even if 2063 * the lifespan is exceeded. 2064 */ 2065 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 2066 &err_chk_p); 2067 2068 /* FIXME: 2069 * If the re-build failed, what is the proper error path 2070 * from here? 2071 * 2072 * [We should abort the association. --piggy] 2073 */ 2074 if (!new_asoc) { 2075 /* FIXME: Several errors are possible. A bad cookie should 2076 * be silently discarded, but think about logging it too. 2077 */ 2078 switch (error) { 2079 case -SCTP_IERROR_NOMEM: 2080 goto nomem; 2081 2082 case -SCTP_IERROR_STALE_COOKIE: 2083 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 2084 err_chk_p); 2085 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2086 case -SCTP_IERROR_BAD_SIG: 2087 default: 2088 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2089 } 2090 } 2091 2092 /* Set temp so that it won't be added into hashtable */ 2093 new_asoc->temp = 1; 2094 2095 /* Compare the tie_tag in cookie with the verification tag of 2096 * current association. 2097 */ 2098 action = sctp_tietags_compare(new_asoc, asoc); 2099 2100 switch (action) { 2101 case 'A': /* Association restart. */ 2102 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands, 2103 new_asoc); 2104 break; 2105 2106 case 'B': /* Collision case B. */ 2107 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands, 2108 new_asoc); 2109 break; 2110 2111 case 'C': /* Collision case C. */ 2112 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands, 2113 new_asoc); 2114 break; 2115 2116 case 'D': /* Collision case D. */ 2117 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands, 2118 new_asoc); 2119 break; 2120 2121 default: /* Discard packet for all others. */ 2122 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2123 break; 2124 } 2125 2126 /* Delete the tempory new association. */ 2127 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc)); 2128 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2129 2130 /* Restore association pointer to provide SCTP command interpeter 2131 * with a valid context in case it needs to manipulate 2132 * the queues */ 2133 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, 2134 SCTP_ASOC((struct sctp_association *)asoc)); 2135 2136 return retval; 2137 2138 nomem: 2139 return SCTP_DISPOSITION_NOMEM; 2140 } 2141 2142 /* 2143 * Process an ABORT. (SHUTDOWN-PENDING state) 2144 * 2145 * See sctp_sf_do_9_1_abort(). 2146 */ 2147 sctp_disposition_t sctp_sf_shutdown_pending_abort( 2148 struct net *net, 2149 const struct sctp_endpoint *ep, 2150 const struct sctp_association *asoc, 2151 const sctp_subtype_t type, 2152 void *arg, 2153 sctp_cmd_seq_t *commands) 2154 { 2155 struct sctp_chunk *chunk = arg; 2156 2157 if (!sctp_vtag_verify_either(chunk, asoc)) 2158 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2159 2160 /* Make sure that the ABORT chunk has a valid length. 2161 * Since this is an ABORT chunk, we have to discard it 2162 * because of the following text: 2163 * RFC 2960, Section 3.3.7 2164 * If an endpoint receives an ABORT with a format error or for an 2165 * association that doesn't exist, it MUST silently discard it. 2166 * Because the length is "invalid", we can't really discard just 2167 * as we do not know its true length. So, to be safe, discard the 2168 * packet. 2169 */ 2170 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2171 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2172 2173 /* ADD-IP: Special case for ABORT chunks 2174 * F4) One special consideration is that ABORT Chunks arriving 2175 * destined to the IP address being deleted MUST be 2176 * ignored (see Section 5.3.1 for further details). 2177 */ 2178 if (SCTP_ADDR_DEL == 2179 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2180 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2181 2182 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2183 } 2184 2185 /* 2186 * Process an ABORT. (SHUTDOWN-SENT state) 2187 * 2188 * See sctp_sf_do_9_1_abort(). 2189 */ 2190 sctp_disposition_t sctp_sf_shutdown_sent_abort(struct net *net, 2191 const struct sctp_endpoint *ep, 2192 const struct sctp_association *asoc, 2193 const sctp_subtype_t type, 2194 void *arg, 2195 sctp_cmd_seq_t *commands) 2196 { 2197 struct sctp_chunk *chunk = arg; 2198 2199 if (!sctp_vtag_verify_either(chunk, asoc)) 2200 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2201 2202 /* Make sure that the ABORT chunk has a valid length. 2203 * Since this is an ABORT chunk, we have to discard it 2204 * because of the following text: 2205 * RFC 2960, Section 3.3.7 2206 * If an endpoint receives an ABORT with a format error or for an 2207 * association that doesn't exist, it MUST silently discard it. 2208 * Because the length is "invalid", we can't really discard just 2209 * as we do not know its true length. So, to be safe, discard the 2210 * packet. 2211 */ 2212 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2213 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2214 2215 /* ADD-IP: Special case for ABORT chunks 2216 * F4) One special consideration is that ABORT Chunks arriving 2217 * destined to the IP address being deleted MUST be 2218 * ignored (see Section 5.3.1 for further details). 2219 */ 2220 if (SCTP_ADDR_DEL == 2221 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2222 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2223 2224 /* Stop the T2-shutdown timer. */ 2225 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2226 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2227 2228 /* Stop the T5-shutdown guard timer. */ 2229 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2230 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2231 2232 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2233 } 2234 2235 /* 2236 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2237 * 2238 * See sctp_sf_do_9_1_abort(). 2239 */ 2240 sctp_disposition_t sctp_sf_shutdown_ack_sent_abort( 2241 struct net *net, 2242 const struct sctp_endpoint *ep, 2243 const struct sctp_association *asoc, 2244 const sctp_subtype_t type, 2245 void *arg, 2246 sctp_cmd_seq_t *commands) 2247 { 2248 /* The same T2 timer, so we should be able to use 2249 * common function with the SHUTDOWN-SENT state. 2250 */ 2251 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands); 2252 } 2253 2254 /* 2255 * Handle an Error received in COOKIE_ECHOED state. 2256 * 2257 * Only handle the error type of stale COOKIE Error, the other errors will 2258 * be ignored. 2259 * 2260 * Inputs 2261 * (endpoint, asoc, chunk) 2262 * 2263 * Outputs 2264 * (asoc, reply_msg, msg_up, timers, counters) 2265 * 2266 * The return value is the disposition of the chunk. 2267 */ 2268 sctp_disposition_t sctp_sf_cookie_echoed_err(struct net *net, 2269 const struct sctp_endpoint *ep, 2270 const struct sctp_association *asoc, 2271 const sctp_subtype_t type, 2272 void *arg, 2273 sctp_cmd_seq_t *commands) 2274 { 2275 struct sctp_chunk *chunk = arg; 2276 sctp_errhdr_t *err; 2277 2278 if (!sctp_vtag_verify(chunk, asoc)) 2279 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2280 2281 /* Make sure that the ERROR chunk has a valid length. 2282 * The parameter walking depends on this as well. 2283 */ 2284 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 2285 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2286 commands); 2287 2288 /* Process the error here */ 2289 /* FUTURE FIXME: When PR-SCTP related and other optional 2290 * parms are emitted, this will have to change to handle multiple 2291 * errors. 2292 */ 2293 sctp_walk_errors(err, chunk->chunk_hdr) { 2294 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2295 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type, 2296 arg, commands); 2297 } 2298 2299 /* It is possible to have malformed error causes, and that 2300 * will cause us to end the walk early. However, since 2301 * we are discarding the packet, there should be no adverse 2302 * affects. 2303 */ 2304 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2305 } 2306 2307 /* 2308 * Handle a Stale COOKIE Error 2309 * 2310 * Section: 5.2.6 Handle Stale COOKIE Error 2311 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2312 * one of the following three alternatives. 2313 * ... 2314 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2315 * Preservative parameter requesting an extension to the lifetime of 2316 * the State Cookie. When calculating the time extension, an 2317 * implementation SHOULD use the RTT information measured based on the 2318 * previous COOKIE ECHO / ERROR exchange, and should add no more 2319 * than 1 second beyond the measured RTT, due to long State Cookie 2320 * lifetimes making the endpoint more subject to a replay attack. 2321 * 2322 * Verification Tag: Not explicit, but safe to ignore. 2323 * 2324 * Inputs 2325 * (endpoint, asoc, chunk) 2326 * 2327 * Outputs 2328 * (asoc, reply_msg, msg_up, timers, counters) 2329 * 2330 * The return value is the disposition of the chunk. 2331 */ 2332 static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net, 2333 const struct sctp_endpoint *ep, 2334 const struct sctp_association *asoc, 2335 const sctp_subtype_t type, 2336 void *arg, 2337 sctp_cmd_seq_t *commands) 2338 { 2339 struct sctp_chunk *chunk = arg; 2340 u32 stale; 2341 sctp_cookie_preserve_param_t bht; 2342 sctp_errhdr_t *err; 2343 struct sctp_chunk *reply; 2344 struct sctp_bind_addr *bp; 2345 int attempts = asoc->init_err_counter + 1; 2346 2347 if (attempts > asoc->max_init_attempts) { 2348 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2349 SCTP_ERROR(ETIMEDOUT)); 2350 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2351 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2352 return SCTP_DISPOSITION_DELETE_TCB; 2353 } 2354 2355 err = (sctp_errhdr_t *)(chunk->skb->data); 2356 2357 /* When calculating the time extension, an implementation 2358 * SHOULD use the RTT information measured based on the 2359 * previous COOKIE ECHO / ERROR exchange, and should add no 2360 * more than 1 second beyond the measured RTT, due to long 2361 * State Cookie lifetimes making the endpoint more subject to 2362 * a replay attack. 2363 * Measure of Staleness's unit is usec. (1/1000000 sec) 2364 * Suggested Cookie Life-span Increment's unit is msec. 2365 * (1/1000 sec) 2366 * In general, if you use the suggested cookie life, the value 2367 * found in the field of measure of staleness should be doubled 2368 * to give ample time to retransmit the new cookie and thus 2369 * yield a higher probability of success on the reattempt. 2370 */ 2371 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t))); 2372 stale = (stale * 2) / 1000; 2373 2374 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2375 bht.param_hdr.length = htons(sizeof(bht)); 2376 bht.lifespan_increment = htonl(stale); 2377 2378 /* Build that new INIT chunk. */ 2379 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2380 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2381 if (!reply) 2382 goto nomem; 2383 2384 sctp_addto_chunk(reply, sizeof(bht), &bht); 2385 2386 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2387 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2388 2389 /* Stop pending T3-rtx and heartbeat timers */ 2390 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2391 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2392 2393 /* Delete non-primary peer ip addresses since we are transitioning 2394 * back to the COOKIE-WAIT state 2395 */ 2396 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2397 2398 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2399 * resend 2400 */ 2401 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2402 SCTP_TRANSPORT(asoc->peer.primary_path)); 2403 2404 /* Cast away the const modifier, as we want to just 2405 * rerun it through as a sideffect. 2406 */ 2407 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2408 2409 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2410 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2411 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2412 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2413 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2414 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2415 2416 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2417 2418 return SCTP_DISPOSITION_CONSUME; 2419 2420 nomem: 2421 return SCTP_DISPOSITION_NOMEM; 2422 } 2423 2424 /* 2425 * Process an ABORT. 2426 * 2427 * Section: 9.1 2428 * After checking the Verification Tag, the receiving endpoint shall 2429 * remove the association from its record, and shall report the 2430 * termination to its upper layer. 2431 * 2432 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2433 * B) Rules for packet carrying ABORT: 2434 * 2435 * - The endpoint shall always fill in the Verification Tag field of the 2436 * outbound packet with the destination endpoint's tag value if it 2437 * is known. 2438 * 2439 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2440 * MUST follow the procedure described in Section 8.4. 2441 * 2442 * - The receiver MUST accept the packet if the Verification Tag 2443 * matches either its own tag, OR the tag of its peer. Otherwise, the 2444 * receiver MUST silently discard the packet and take no further 2445 * action. 2446 * 2447 * Inputs 2448 * (endpoint, asoc, chunk) 2449 * 2450 * Outputs 2451 * (asoc, reply_msg, msg_up, timers, counters) 2452 * 2453 * The return value is the disposition of the chunk. 2454 */ 2455 sctp_disposition_t sctp_sf_do_9_1_abort(struct net *net, 2456 const struct sctp_endpoint *ep, 2457 const struct sctp_association *asoc, 2458 const sctp_subtype_t type, 2459 void *arg, 2460 sctp_cmd_seq_t *commands) 2461 { 2462 struct sctp_chunk *chunk = arg; 2463 2464 if (!sctp_vtag_verify_either(chunk, asoc)) 2465 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2466 2467 /* Make sure that the ABORT chunk has a valid length. 2468 * Since this is an ABORT chunk, we have to discard it 2469 * because of the following text: 2470 * RFC 2960, Section 3.3.7 2471 * If an endpoint receives an ABORT with a format error or for an 2472 * association that doesn't exist, it MUST silently discard it. 2473 * Because the length is "invalid", we can't really discard just 2474 * as we do not know its true length. So, to be safe, discard the 2475 * packet. 2476 */ 2477 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2478 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2479 2480 /* ADD-IP: Special case for ABORT chunks 2481 * F4) One special consideration is that ABORT Chunks arriving 2482 * destined to the IP address being deleted MUST be 2483 * ignored (see Section 5.3.1 for further details). 2484 */ 2485 if (SCTP_ADDR_DEL == 2486 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2487 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2488 2489 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2490 } 2491 2492 static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net, 2493 const struct sctp_endpoint *ep, 2494 const struct sctp_association *asoc, 2495 const sctp_subtype_t type, 2496 void *arg, 2497 sctp_cmd_seq_t *commands) 2498 { 2499 struct sctp_chunk *chunk = arg; 2500 unsigned int len; 2501 __be16 error = SCTP_ERROR_NO_ERROR; 2502 2503 /* See if we have an error cause code in the chunk. */ 2504 len = ntohs(chunk->chunk_hdr->length); 2505 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) { 2506 2507 sctp_errhdr_t *err; 2508 sctp_walk_errors(err, chunk->chunk_hdr); 2509 if ((void *)err != (void *)chunk->chunk_end) 2510 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2511 2512 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2513 } 2514 2515 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2516 /* ASSOC_FAILED will DELETE_TCB. */ 2517 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2518 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2519 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 2520 2521 return SCTP_DISPOSITION_ABORT; 2522 } 2523 2524 /* 2525 * Process an ABORT. (COOKIE-WAIT state) 2526 * 2527 * See sctp_sf_do_9_1_abort() above. 2528 */ 2529 sctp_disposition_t sctp_sf_cookie_wait_abort(struct net *net, 2530 const struct sctp_endpoint *ep, 2531 const struct sctp_association *asoc, 2532 const sctp_subtype_t type, 2533 void *arg, 2534 sctp_cmd_seq_t *commands) 2535 { 2536 struct sctp_chunk *chunk = arg; 2537 unsigned int len; 2538 __be16 error = SCTP_ERROR_NO_ERROR; 2539 2540 if (!sctp_vtag_verify_either(chunk, asoc)) 2541 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2542 2543 /* Make sure that the ABORT chunk has a valid length. 2544 * Since this is an ABORT chunk, we have to discard it 2545 * because of the following text: 2546 * RFC 2960, Section 3.3.7 2547 * If an endpoint receives an ABORT with a format error or for an 2548 * association that doesn't exist, it MUST silently discard it. 2549 * Because the length is "invalid", we can't really discard just 2550 * as we do not know its true length. So, to be safe, discard the 2551 * packet. 2552 */ 2553 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2554 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2555 2556 /* See if we have an error cause code in the chunk. */ 2557 len = ntohs(chunk->chunk_hdr->length); 2558 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2559 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2560 2561 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc, 2562 chunk->transport); 2563 } 2564 2565 /* 2566 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2567 */ 2568 sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(struct net *net, 2569 const struct sctp_endpoint *ep, 2570 const struct sctp_association *asoc, 2571 const sctp_subtype_t type, 2572 void *arg, 2573 sctp_cmd_seq_t *commands) 2574 { 2575 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR, 2576 ENOPROTOOPT, asoc, 2577 (struct sctp_transport *)arg); 2578 } 2579 2580 /* 2581 * Process an ABORT. (COOKIE-ECHOED state) 2582 */ 2583 sctp_disposition_t sctp_sf_cookie_echoed_abort(struct net *net, 2584 const struct sctp_endpoint *ep, 2585 const struct sctp_association *asoc, 2586 const sctp_subtype_t type, 2587 void *arg, 2588 sctp_cmd_seq_t *commands) 2589 { 2590 /* There is a single T1 timer, so we should be able to use 2591 * common function with the COOKIE-WAIT state. 2592 */ 2593 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands); 2594 } 2595 2596 /* 2597 * Stop T1 timer and abort association with "INIT failed". 2598 * 2599 * This is common code called by several sctp_sf_*_abort() functions above. 2600 */ 2601 static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net, 2602 sctp_cmd_seq_t *commands, 2603 __be16 error, int sk_err, 2604 const struct sctp_association *asoc, 2605 struct sctp_transport *transport) 2606 { 2607 pr_debug("%s: ABORT received (INIT)\n", __func__); 2608 2609 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2610 SCTP_STATE(SCTP_STATE_CLOSED)); 2611 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2612 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2613 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2614 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2615 /* CMD_INIT_FAILED will DELETE_TCB. */ 2616 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2617 SCTP_PERR(error)); 2618 2619 return SCTP_DISPOSITION_ABORT; 2620 } 2621 2622 /* 2623 * sctp_sf_do_9_2_shut 2624 * 2625 * Section: 9.2 2626 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2627 * - enter the SHUTDOWN-RECEIVED state, 2628 * 2629 * - stop accepting new data from its SCTP user 2630 * 2631 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2632 * that all its outstanding DATA chunks have been received by the 2633 * SHUTDOWN sender. 2634 * 2635 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2636 * send a SHUTDOWN in response to a ULP request. And should discard 2637 * subsequent SHUTDOWN chunks. 2638 * 2639 * If there are still outstanding DATA chunks left, the SHUTDOWN 2640 * receiver shall continue to follow normal data transmission 2641 * procedures defined in Section 6 until all outstanding DATA chunks 2642 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2643 * new data from its SCTP user. 2644 * 2645 * Verification Tag: 8.5 Verification Tag [Normal verification] 2646 * 2647 * Inputs 2648 * (endpoint, asoc, chunk) 2649 * 2650 * Outputs 2651 * (asoc, reply_msg, msg_up, timers, counters) 2652 * 2653 * The return value is the disposition of the chunk. 2654 */ 2655 sctp_disposition_t sctp_sf_do_9_2_shutdown(struct net *net, 2656 const struct sctp_endpoint *ep, 2657 const struct sctp_association *asoc, 2658 const sctp_subtype_t type, 2659 void *arg, 2660 sctp_cmd_seq_t *commands) 2661 { 2662 struct sctp_chunk *chunk = arg; 2663 sctp_shutdownhdr_t *sdh; 2664 sctp_disposition_t disposition; 2665 struct sctp_ulpevent *ev; 2666 __u32 ctsn; 2667 2668 if (!sctp_vtag_verify(chunk, asoc)) 2669 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2670 2671 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2672 if (!sctp_chunk_length_valid(chunk, 2673 sizeof(struct sctp_shutdown_chunk_t))) 2674 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2675 commands); 2676 2677 /* Convert the elaborate header. */ 2678 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2679 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t)); 2680 chunk->subh.shutdown_hdr = sdh; 2681 ctsn = ntohl(sdh->cum_tsn_ack); 2682 2683 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2684 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2685 asoc->ctsn_ack_point); 2686 2687 return SCTP_DISPOSITION_DISCARD; 2688 } 2689 2690 /* If Cumulative TSN Ack beyond the max tsn currently 2691 * send, terminating the association and respond to the 2692 * sender with an ABORT. 2693 */ 2694 if (!TSN_lt(ctsn, asoc->next_tsn)) 2695 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2696 2697 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2698 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2699 * inform the application that it should cease sending data. 2700 */ 2701 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2702 if (!ev) { 2703 disposition = SCTP_DISPOSITION_NOMEM; 2704 goto out; 2705 } 2706 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2707 2708 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2709 * - enter the SHUTDOWN-RECEIVED state, 2710 * - stop accepting new data from its SCTP user 2711 * 2712 * [This is implicit in the new state.] 2713 */ 2714 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2715 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2716 disposition = SCTP_DISPOSITION_CONSUME; 2717 2718 if (sctp_outq_is_empty(&asoc->outqueue)) { 2719 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type, 2720 arg, commands); 2721 } 2722 2723 if (SCTP_DISPOSITION_NOMEM == disposition) 2724 goto out; 2725 2726 /* - verify, by checking the Cumulative TSN Ack field of the 2727 * chunk, that all its outstanding DATA chunks have been 2728 * received by the SHUTDOWN sender. 2729 */ 2730 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2731 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2732 2733 out: 2734 return disposition; 2735 } 2736 2737 /* 2738 * sctp_sf_do_9_2_shut_ctsn 2739 * 2740 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2741 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2742 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2743 * MUST be processed. 2744 */ 2745 sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(struct net *net, 2746 const struct sctp_endpoint *ep, 2747 const struct sctp_association *asoc, 2748 const sctp_subtype_t type, 2749 void *arg, 2750 sctp_cmd_seq_t *commands) 2751 { 2752 struct sctp_chunk *chunk = arg; 2753 sctp_shutdownhdr_t *sdh; 2754 __u32 ctsn; 2755 2756 if (!sctp_vtag_verify(chunk, asoc)) 2757 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2758 2759 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2760 if (!sctp_chunk_length_valid(chunk, 2761 sizeof(struct sctp_shutdown_chunk_t))) 2762 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2763 commands); 2764 2765 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2766 ctsn = ntohl(sdh->cum_tsn_ack); 2767 2768 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2769 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2770 asoc->ctsn_ack_point); 2771 2772 return SCTP_DISPOSITION_DISCARD; 2773 } 2774 2775 /* If Cumulative TSN Ack beyond the max tsn currently 2776 * send, terminating the association and respond to the 2777 * sender with an ABORT. 2778 */ 2779 if (!TSN_lt(ctsn, asoc->next_tsn)) 2780 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2781 2782 /* verify, by checking the Cumulative TSN Ack field of the 2783 * chunk, that all its outstanding DATA chunks have been 2784 * received by the SHUTDOWN sender. 2785 */ 2786 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2787 SCTP_BE32(sdh->cum_tsn_ack)); 2788 2789 return SCTP_DISPOSITION_CONSUME; 2790 } 2791 2792 /* RFC 2960 9.2 2793 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2794 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2795 * transport addresses (either in the IP addresses or in the INIT chunk) 2796 * that belong to this association, it should discard the INIT chunk and 2797 * retransmit the SHUTDOWN ACK chunk. 2798 */ 2799 sctp_disposition_t sctp_sf_do_9_2_reshutack(struct net *net, 2800 const struct sctp_endpoint *ep, 2801 const struct sctp_association *asoc, 2802 const sctp_subtype_t type, 2803 void *arg, 2804 sctp_cmd_seq_t *commands) 2805 { 2806 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 2807 struct sctp_chunk *reply; 2808 2809 /* Make sure that the chunk has a valid length */ 2810 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 2811 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2812 commands); 2813 2814 /* Since we are not going to really process this INIT, there 2815 * is no point in verifying chunk boundries. Just generate 2816 * the SHUTDOWN ACK. 2817 */ 2818 reply = sctp_make_shutdown_ack(asoc, chunk); 2819 if (NULL == reply) 2820 goto nomem; 2821 2822 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2823 * the T2-SHUTDOWN timer. 2824 */ 2825 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2826 2827 /* and restart the T2-shutdown timer. */ 2828 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2829 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2830 2831 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2832 2833 return SCTP_DISPOSITION_CONSUME; 2834 nomem: 2835 return SCTP_DISPOSITION_NOMEM; 2836 } 2837 2838 /* 2839 * sctp_sf_do_ecn_cwr 2840 * 2841 * Section: Appendix A: Explicit Congestion Notification 2842 * 2843 * CWR: 2844 * 2845 * RFC 2481 details a specific bit for a sender to send in the header of 2846 * its next outbound TCP segment to indicate to its peer that it has 2847 * reduced its congestion window. This is termed the CWR bit. For 2848 * SCTP the same indication is made by including the CWR chunk. 2849 * This chunk contains one data element, i.e. the TSN number that 2850 * was sent in the ECNE chunk. This element represents the lowest 2851 * TSN number in the datagram that was originally marked with the 2852 * CE bit. 2853 * 2854 * Verification Tag: 8.5 Verification Tag [Normal verification] 2855 * Inputs 2856 * (endpoint, asoc, chunk) 2857 * 2858 * Outputs 2859 * (asoc, reply_msg, msg_up, timers, counters) 2860 * 2861 * The return value is the disposition of the chunk. 2862 */ 2863 sctp_disposition_t sctp_sf_do_ecn_cwr(struct net *net, 2864 const struct sctp_endpoint *ep, 2865 const struct sctp_association *asoc, 2866 const sctp_subtype_t type, 2867 void *arg, 2868 sctp_cmd_seq_t *commands) 2869 { 2870 sctp_cwrhdr_t *cwr; 2871 struct sctp_chunk *chunk = arg; 2872 u32 lowest_tsn; 2873 2874 if (!sctp_vtag_verify(chunk, asoc)) 2875 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2876 2877 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2878 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2879 commands); 2880 2881 cwr = (sctp_cwrhdr_t *) chunk->skb->data; 2882 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t)); 2883 2884 lowest_tsn = ntohl(cwr->lowest_tsn); 2885 2886 /* Does this CWR ack the last sent congestion notification? */ 2887 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 2888 /* Stop sending ECNE. */ 2889 sctp_add_cmd_sf(commands, 2890 SCTP_CMD_ECN_CWR, 2891 SCTP_U32(lowest_tsn)); 2892 } 2893 return SCTP_DISPOSITION_CONSUME; 2894 } 2895 2896 /* 2897 * sctp_sf_do_ecne 2898 * 2899 * Section: Appendix A: Explicit Congestion Notification 2900 * 2901 * ECN-Echo 2902 * 2903 * RFC 2481 details a specific bit for a receiver to send back in its 2904 * TCP acknowledgements to notify the sender of the Congestion 2905 * Experienced (CE) bit having arrived from the network. For SCTP this 2906 * same indication is made by including the ECNE chunk. This chunk 2907 * contains one data element, i.e. the lowest TSN associated with the IP 2908 * datagram marked with the CE bit..... 2909 * 2910 * Verification Tag: 8.5 Verification Tag [Normal verification] 2911 * Inputs 2912 * (endpoint, asoc, chunk) 2913 * 2914 * Outputs 2915 * (asoc, reply_msg, msg_up, timers, counters) 2916 * 2917 * The return value is the disposition of the chunk. 2918 */ 2919 sctp_disposition_t sctp_sf_do_ecne(struct net *net, 2920 const struct sctp_endpoint *ep, 2921 const struct sctp_association *asoc, 2922 const sctp_subtype_t type, 2923 void *arg, 2924 sctp_cmd_seq_t *commands) 2925 { 2926 sctp_ecnehdr_t *ecne; 2927 struct sctp_chunk *chunk = arg; 2928 2929 if (!sctp_vtag_verify(chunk, asoc)) 2930 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2931 2932 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2933 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2934 commands); 2935 2936 ecne = (sctp_ecnehdr_t *) chunk->skb->data; 2937 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t)); 2938 2939 /* If this is a newer ECNE than the last CWR packet we sent out */ 2940 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 2941 SCTP_U32(ntohl(ecne->lowest_tsn))); 2942 2943 return SCTP_DISPOSITION_CONSUME; 2944 } 2945 2946 /* 2947 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 2948 * 2949 * The SCTP endpoint MUST always acknowledge the reception of each valid 2950 * DATA chunk. 2951 * 2952 * The guidelines on delayed acknowledgement algorithm specified in 2953 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 2954 * acknowledgement SHOULD be generated for at least every second packet 2955 * (not every second DATA chunk) received, and SHOULD be generated within 2956 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 2957 * situations it may be beneficial for an SCTP transmitter to be more 2958 * conservative than the algorithms detailed in this document allow. 2959 * However, an SCTP transmitter MUST NOT be more aggressive than the 2960 * following algorithms allow. 2961 * 2962 * A SCTP receiver MUST NOT generate more than one SACK for every 2963 * incoming packet, other than to update the offered window as the 2964 * receiving application consumes new data. 2965 * 2966 * Verification Tag: 8.5 Verification Tag [Normal verification] 2967 * 2968 * Inputs 2969 * (endpoint, asoc, chunk) 2970 * 2971 * Outputs 2972 * (asoc, reply_msg, msg_up, timers, counters) 2973 * 2974 * The return value is the disposition of the chunk. 2975 */ 2976 sctp_disposition_t sctp_sf_eat_data_6_2(struct net *net, 2977 const struct sctp_endpoint *ep, 2978 const struct sctp_association *asoc, 2979 const sctp_subtype_t type, 2980 void *arg, 2981 sctp_cmd_seq_t *commands) 2982 { 2983 struct sctp_chunk *chunk = arg; 2984 sctp_arg_t force = SCTP_NOFORCE(); 2985 int error; 2986 2987 if (!sctp_vtag_verify(chunk, asoc)) { 2988 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2989 SCTP_NULL()); 2990 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2991 } 2992 2993 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_data_chunk))) 2994 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2995 commands); 2996 2997 error = sctp_eat_data(asoc, chunk, commands); 2998 switch (error) { 2999 case SCTP_IERROR_NO_ERROR: 3000 break; 3001 case SCTP_IERROR_HIGH_TSN: 3002 case SCTP_IERROR_BAD_STREAM: 3003 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3004 goto discard_noforce; 3005 case SCTP_IERROR_DUP_TSN: 3006 case SCTP_IERROR_IGNORE_TSN: 3007 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3008 goto discard_force; 3009 case SCTP_IERROR_NO_DATA: 3010 return SCTP_DISPOSITION_ABORT; 3011 case SCTP_IERROR_PROTO_VIOLATION: 3012 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3013 (u8 *)chunk->subh.data_hdr, 3014 sizeof(struct sctp_datahdr)); 3015 default: 3016 BUG(); 3017 } 3018 3019 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 3020 force = SCTP_FORCE(); 3021 3022 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 3023 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3024 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3025 } 3026 3027 /* If this is the last chunk in a packet, we need to count it 3028 * toward sack generation. Note that we need to SACK every 3029 * OTHER packet containing data chunks, EVEN IF WE DISCARD 3030 * THEM. We elect to NOT generate SACK's if the chunk fails 3031 * the verification tag test. 3032 * 3033 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3034 * 3035 * The SCTP endpoint MUST always acknowledge the reception of 3036 * each valid DATA chunk. 3037 * 3038 * The guidelines on delayed acknowledgement algorithm 3039 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 3040 * Specifically, an acknowledgement SHOULD be generated for at 3041 * least every second packet (not every second DATA chunk) 3042 * received, and SHOULD be generated within 200 ms of the 3043 * arrival of any unacknowledged DATA chunk. In some 3044 * situations it may be beneficial for an SCTP transmitter to 3045 * be more conservative than the algorithms detailed in this 3046 * document allow. However, an SCTP transmitter MUST NOT be 3047 * more aggressive than the following algorithms allow. 3048 */ 3049 if (chunk->end_of_packet) 3050 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3051 3052 return SCTP_DISPOSITION_CONSUME; 3053 3054 discard_force: 3055 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3056 * 3057 * When a packet arrives with duplicate DATA chunk(s) and with 3058 * no new DATA chunk(s), the endpoint MUST immediately send a 3059 * SACK with no delay. If a packet arrives with duplicate 3060 * DATA chunk(s) bundled with new DATA chunks, the endpoint 3061 * MAY immediately send a SACK. Normally receipt of duplicate 3062 * DATA chunks will occur when the original SACK chunk was lost 3063 * and the peer's RTO has expired. The duplicate TSN number(s) 3064 * SHOULD be reported in the SACK as duplicate. 3065 */ 3066 /* In our case, we split the MAY SACK advice up whether or not 3067 * the last chunk is a duplicate.' 3068 */ 3069 if (chunk->end_of_packet) 3070 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3071 return SCTP_DISPOSITION_DISCARD; 3072 3073 discard_noforce: 3074 if (chunk->end_of_packet) 3075 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3076 3077 return SCTP_DISPOSITION_DISCARD; 3078 } 3079 3080 /* 3081 * sctp_sf_eat_data_fast_4_4 3082 * 3083 * Section: 4 (4) 3084 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 3085 * DATA chunks without delay. 3086 * 3087 * Verification Tag: 8.5 Verification Tag [Normal verification] 3088 * Inputs 3089 * (endpoint, asoc, chunk) 3090 * 3091 * Outputs 3092 * (asoc, reply_msg, msg_up, timers, counters) 3093 * 3094 * The return value is the disposition of the chunk. 3095 */ 3096 sctp_disposition_t sctp_sf_eat_data_fast_4_4(struct net *net, 3097 const struct sctp_endpoint *ep, 3098 const struct sctp_association *asoc, 3099 const sctp_subtype_t type, 3100 void *arg, 3101 sctp_cmd_seq_t *commands) 3102 { 3103 struct sctp_chunk *chunk = arg; 3104 int error; 3105 3106 if (!sctp_vtag_verify(chunk, asoc)) { 3107 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3108 SCTP_NULL()); 3109 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3110 } 3111 3112 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_data_chunk))) 3113 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3114 commands); 3115 3116 error = sctp_eat_data(asoc, chunk, commands); 3117 switch (error) { 3118 case SCTP_IERROR_NO_ERROR: 3119 case SCTP_IERROR_HIGH_TSN: 3120 case SCTP_IERROR_DUP_TSN: 3121 case SCTP_IERROR_IGNORE_TSN: 3122 case SCTP_IERROR_BAD_STREAM: 3123 break; 3124 case SCTP_IERROR_NO_DATA: 3125 return SCTP_DISPOSITION_ABORT; 3126 case SCTP_IERROR_PROTO_VIOLATION: 3127 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3128 (u8 *)chunk->subh.data_hdr, 3129 sizeof(struct sctp_datahdr)); 3130 default: 3131 BUG(); 3132 } 3133 3134 /* Go a head and force a SACK, since we are shutting down. */ 3135 3136 /* Implementor's Guide. 3137 * 3138 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3139 * respond to each received packet containing one or more DATA chunk(s) 3140 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3141 */ 3142 if (chunk->end_of_packet) { 3143 /* We must delay the chunk creation since the cumulative 3144 * TSN has not been updated yet. 3145 */ 3146 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3147 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3148 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3149 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3150 } 3151 3152 return SCTP_DISPOSITION_CONSUME; 3153 } 3154 3155 /* 3156 * Section: 6.2 Processing a Received SACK 3157 * D) Any time a SACK arrives, the endpoint performs the following: 3158 * 3159 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3160 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3161 * increasing, a SACK whose Cumulative TSN Ack is less than the 3162 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3163 * 3164 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3165 * of bytes still outstanding after processing the Cumulative TSN Ack 3166 * and the Gap Ack Blocks. 3167 * 3168 * iii) If the SACK is missing a TSN that was previously 3169 * acknowledged via a Gap Ack Block (e.g., the data receiver 3170 * reneged on the data), then mark the corresponding DATA chunk 3171 * as available for retransmit: Mark it as missing for fast 3172 * retransmit as described in Section 7.2.4 and if no retransmit 3173 * timer is running for the destination address to which the DATA 3174 * chunk was originally transmitted, then T3-rtx is started for 3175 * that destination address. 3176 * 3177 * Verification Tag: 8.5 Verification Tag [Normal verification] 3178 * 3179 * Inputs 3180 * (endpoint, asoc, chunk) 3181 * 3182 * Outputs 3183 * (asoc, reply_msg, msg_up, timers, counters) 3184 * 3185 * The return value is the disposition of the chunk. 3186 */ 3187 sctp_disposition_t sctp_sf_eat_sack_6_2(struct net *net, 3188 const struct sctp_endpoint *ep, 3189 const struct sctp_association *asoc, 3190 const sctp_subtype_t type, 3191 void *arg, 3192 sctp_cmd_seq_t *commands) 3193 { 3194 struct sctp_chunk *chunk = arg; 3195 sctp_sackhdr_t *sackh; 3196 __u32 ctsn; 3197 3198 if (!sctp_vtag_verify(chunk, asoc)) 3199 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3200 3201 /* Make sure that the SACK chunk has a valid length. */ 3202 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t))) 3203 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3204 commands); 3205 3206 /* Pull the SACK chunk from the data buffer */ 3207 sackh = sctp_sm_pull_sack(chunk); 3208 /* Was this a bogus SACK? */ 3209 if (!sackh) 3210 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3211 chunk->subh.sack_hdr = sackh; 3212 ctsn = ntohl(sackh->cum_tsn_ack); 3213 3214 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3215 * Ack Point, then drop the SACK. Since Cumulative TSN 3216 * Ack is monotonically increasing, a SACK whose 3217 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3218 * Point indicates an out-of-order SACK. 3219 */ 3220 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3221 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 3222 asoc->ctsn_ack_point); 3223 3224 return SCTP_DISPOSITION_DISCARD; 3225 } 3226 3227 /* If Cumulative TSN Ack beyond the max tsn currently 3228 * send, terminating the association and respond to the 3229 * sender with an ABORT. 3230 */ 3231 if (!TSN_lt(ctsn, asoc->next_tsn)) 3232 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 3233 3234 /* Return this SACK for further processing. */ 3235 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk)); 3236 3237 /* Note: We do the rest of the work on the PROCESS_SACK 3238 * sideeffect. 3239 */ 3240 return SCTP_DISPOSITION_CONSUME; 3241 } 3242 3243 /* 3244 * Generate an ABORT in response to a packet. 3245 * 3246 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3247 * 3248 * 8) The receiver should respond to the sender of the OOTB packet with 3249 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3250 * MUST fill in the Verification Tag field of the outbound packet 3251 * with the value found in the Verification Tag field of the OOTB 3252 * packet and set the T-bit in the Chunk Flags to indicate that the 3253 * Verification Tag is reflected. After sending this ABORT, the 3254 * receiver of the OOTB packet shall discard the OOTB packet and take 3255 * no further action. 3256 * 3257 * Verification Tag: 3258 * 3259 * The return value is the disposition of the chunk. 3260 */ 3261 static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net, 3262 const struct sctp_endpoint *ep, 3263 const struct sctp_association *asoc, 3264 const sctp_subtype_t type, 3265 void *arg, 3266 sctp_cmd_seq_t *commands) 3267 { 3268 struct sctp_packet *packet = NULL; 3269 struct sctp_chunk *chunk = arg; 3270 struct sctp_chunk *abort; 3271 3272 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3273 if (!packet) 3274 return SCTP_DISPOSITION_NOMEM; 3275 3276 /* Make an ABORT. The T bit will be set if the asoc 3277 * is NULL. 3278 */ 3279 abort = sctp_make_abort(asoc, chunk, 0); 3280 if (!abort) { 3281 sctp_ootb_pkt_free(packet); 3282 return SCTP_DISPOSITION_NOMEM; 3283 } 3284 3285 /* Reflect vtag if T-Bit is set */ 3286 if (sctp_test_T_bit(abort)) 3287 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3288 3289 /* Set the skb to the belonging sock for accounting. */ 3290 abort->skb->sk = ep->base.sk; 3291 3292 sctp_packet_append_chunk(packet, abort); 3293 3294 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3295 SCTP_PACKET(packet)); 3296 3297 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3298 3299 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3300 return SCTP_DISPOSITION_CONSUME; 3301 } 3302 3303 /* 3304 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3305 * event as ULP notification for each cause included in the chunk. 3306 * 3307 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3308 * 3309 * The return value is the disposition of the chunk. 3310 */ 3311 sctp_disposition_t sctp_sf_operr_notify(struct net *net, 3312 const struct sctp_endpoint *ep, 3313 const struct sctp_association *asoc, 3314 const sctp_subtype_t type, 3315 void *arg, 3316 sctp_cmd_seq_t *commands) 3317 { 3318 struct sctp_chunk *chunk = arg; 3319 sctp_errhdr_t *err; 3320 3321 if (!sctp_vtag_verify(chunk, asoc)) 3322 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3323 3324 /* Make sure that the ERROR chunk has a valid length. */ 3325 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 3326 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3327 commands); 3328 sctp_walk_errors(err, chunk->chunk_hdr); 3329 if ((void *)err != (void *)chunk->chunk_end) 3330 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3331 (void *)err, commands); 3332 3333 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3334 SCTP_CHUNK(chunk)); 3335 3336 return SCTP_DISPOSITION_CONSUME; 3337 } 3338 3339 /* 3340 * Process an inbound SHUTDOWN ACK. 3341 * 3342 * From Section 9.2: 3343 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3344 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3345 * peer, and remove all record of the association. 3346 * 3347 * The return value is the disposition. 3348 */ 3349 sctp_disposition_t sctp_sf_do_9_2_final(struct net *net, 3350 const struct sctp_endpoint *ep, 3351 const struct sctp_association *asoc, 3352 const sctp_subtype_t type, 3353 void *arg, 3354 sctp_cmd_seq_t *commands) 3355 { 3356 struct sctp_chunk *chunk = arg; 3357 struct sctp_chunk *reply; 3358 struct sctp_ulpevent *ev; 3359 3360 if (!sctp_vtag_verify(chunk, asoc)) 3361 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3362 3363 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3364 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3365 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3366 commands); 3367 /* 10.2 H) SHUTDOWN COMPLETE notification 3368 * 3369 * When SCTP completes the shutdown procedures (section 9.2) this 3370 * notification is passed to the upper layer. 3371 */ 3372 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3373 0, 0, 0, NULL, GFP_ATOMIC); 3374 if (!ev) 3375 goto nomem; 3376 3377 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3378 reply = sctp_make_shutdown_complete(asoc, chunk); 3379 if (!reply) 3380 goto nomem_chunk; 3381 3382 /* Do all the commands now (after allocation), so that we 3383 * have consistent state if memory allocation failes 3384 */ 3385 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3386 3387 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3388 * stop the T2-shutdown timer, 3389 */ 3390 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3391 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3392 3393 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3394 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3395 3396 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3397 SCTP_STATE(SCTP_STATE_CLOSED)); 3398 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 3399 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3400 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3401 3402 /* ...and remove all record of the association. */ 3403 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3404 return SCTP_DISPOSITION_DELETE_TCB; 3405 3406 nomem_chunk: 3407 sctp_ulpevent_free(ev); 3408 nomem: 3409 return SCTP_DISPOSITION_NOMEM; 3410 } 3411 3412 /* 3413 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3414 * 3415 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3416 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3417 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3418 * packet must fill in the Verification Tag field of the outbound 3419 * packet with the Verification Tag received in the SHUTDOWN ACK and 3420 * set the T-bit in the Chunk Flags to indicate that the Verification 3421 * Tag is reflected. 3422 * 3423 * 8) The receiver should respond to the sender of the OOTB packet with 3424 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3425 * MUST fill in the Verification Tag field of the outbound packet 3426 * with the value found in the Verification Tag field of the OOTB 3427 * packet and set the T-bit in the Chunk Flags to indicate that the 3428 * Verification Tag is reflected. After sending this ABORT, the 3429 * receiver of the OOTB packet shall discard the OOTB packet and take 3430 * no further action. 3431 */ 3432 sctp_disposition_t sctp_sf_ootb(struct net *net, 3433 const struct sctp_endpoint *ep, 3434 const struct sctp_association *asoc, 3435 const sctp_subtype_t type, 3436 void *arg, 3437 sctp_cmd_seq_t *commands) 3438 { 3439 struct sctp_chunk *chunk = arg; 3440 struct sk_buff *skb = chunk->skb; 3441 struct sctp_chunkhdr *ch; 3442 sctp_errhdr_t *err; 3443 __u8 *ch_end; 3444 int ootb_shut_ack = 0; 3445 int ootb_cookie_ack = 0; 3446 3447 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3448 3449 ch = (struct sctp_chunkhdr *)chunk->chunk_hdr; 3450 do { 3451 /* Report violation if the chunk is less then minimal */ 3452 if (ntohs(ch->length) < sizeof(*ch)) 3453 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3454 commands); 3455 3456 /* Report violation if chunk len overflows */ 3457 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); 3458 if (ch_end > skb_tail_pointer(skb)) 3459 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3460 commands); 3461 3462 /* Now that we know we at least have a chunk header, 3463 * do things that are type appropriate. 3464 */ 3465 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3466 ootb_shut_ack = 1; 3467 3468 /* RFC 2960, Section 3.3.7 3469 * Moreover, under any circumstances, an endpoint that 3470 * receives an ABORT MUST NOT respond to that ABORT by 3471 * sending an ABORT of its own. 3472 */ 3473 if (SCTP_CID_ABORT == ch->type) 3474 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3475 3476 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 3477 * or a COOKIE ACK the SCTP Packet should be silently 3478 * discarded. 3479 */ 3480 3481 if (SCTP_CID_COOKIE_ACK == ch->type) 3482 ootb_cookie_ack = 1; 3483 3484 if (SCTP_CID_ERROR == ch->type) { 3485 sctp_walk_errors(err, ch) { 3486 if (SCTP_ERROR_STALE_COOKIE == err->cause) { 3487 ootb_cookie_ack = 1; 3488 break; 3489 } 3490 } 3491 } 3492 3493 ch = (struct sctp_chunkhdr *)ch_end; 3494 } while (ch_end < skb_tail_pointer(skb)); 3495 3496 if (ootb_shut_ack) 3497 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands); 3498 else if (ootb_cookie_ack) 3499 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3500 else 3501 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3502 } 3503 3504 /* 3505 * Handle an "Out of the blue" SHUTDOWN ACK. 3506 * 3507 * Section: 8.4 5, sctpimpguide 2.41. 3508 * 3509 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3510 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3511 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3512 * packet must fill in the Verification Tag field of the outbound 3513 * packet with the Verification Tag received in the SHUTDOWN ACK and 3514 * set the T-bit in the Chunk Flags to indicate that the Verification 3515 * Tag is reflected. 3516 * 3517 * Inputs 3518 * (endpoint, asoc, type, arg, commands) 3519 * 3520 * Outputs 3521 * (sctp_disposition_t) 3522 * 3523 * The return value is the disposition of the chunk. 3524 */ 3525 static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net, 3526 const struct sctp_endpoint *ep, 3527 const struct sctp_association *asoc, 3528 const sctp_subtype_t type, 3529 void *arg, 3530 sctp_cmd_seq_t *commands) 3531 { 3532 struct sctp_packet *packet = NULL; 3533 struct sctp_chunk *chunk = arg; 3534 struct sctp_chunk *shut; 3535 3536 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3537 if (!packet) 3538 return SCTP_DISPOSITION_NOMEM; 3539 3540 /* Make an SHUTDOWN_COMPLETE. 3541 * The T bit will be set if the asoc is NULL. 3542 */ 3543 shut = sctp_make_shutdown_complete(asoc, chunk); 3544 if (!shut) { 3545 sctp_ootb_pkt_free(packet); 3546 return SCTP_DISPOSITION_NOMEM; 3547 } 3548 3549 /* Reflect vtag if T-Bit is set */ 3550 if (sctp_test_T_bit(shut)) 3551 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3552 3553 /* Set the skb to the belonging sock for accounting. */ 3554 shut->skb->sk = ep->base.sk; 3555 3556 sctp_packet_append_chunk(packet, shut); 3557 3558 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3559 SCTP_PACKET(packet)); 3560 3561 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3562 3563 /* If the chunk length is invalid, we don't want to process 3564 * the reset of the packet. 3565 */ 3566 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3567 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3568 3569 /* We need to discard the rest of the packet to prevent 3570 * potential bomming attacks from additional bundled chunks. 3571 * This is documented in SCTP Threats ID. 3572 */ 3573 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3574 } 3575 3576 /* 3577 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3578 * 3579 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3580 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3581 * procedures in section 8.4 SHOULD be followed, in other words it 3582 * should be treated as an Out Of The Blue packet. 3583 * [This means that we do NOT check the Verification Tag on these 3584 * chunks. --piggy ] 3585 * 3586 */ 3587 sctp_disposition_t sctp_sf_do_8_5_1_E_sa(struct net *net, 3588 const struct sctp_endpoint *ep, 3589 const struct sctp_association *asoc, 3590 const sctp_subtype_t type, 3591 void *arg, 3592 sctp_cmd_seq_t *commands) 3593 { 3594 struct sctp_chunk *chunk = arg; 3595 3596 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3597 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3598 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3599 commands); 3600 3601 /* Although we do have an association in this case, it corresponds 3602 * to a restarted association. So the packet is treated as an OOTB 3603 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3604 * called with a NULL association. 3605 */ 3606 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3607 3608 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands); 3609 } 3610 3611 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3612 sctp_disposition_t sctp_sf_do_asconf(struct net *net, 3613 const struct sctp_endpoint *ep, 3614 const struct sctp_association *asoc, 3615 const sctp_subtype_t type, void *arg, 3616 sctp_cmd_seq_t *commands) 3617 { 3618 struct sctp_chunk *chunk = arg; 3619 struct sctp_chunk *asconf_ack = NULL; 3620 struct sctp_paramhdr *err_param = NULL; 3621 sctp_addiphdr_t *hdr; 3622 __u32 serial; 3623 3624 if (!sctp_vtag_verify(chunk, asoc)) { 3625 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3626 SCTP_NULL()); 3627 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3628 } 3629 3630 /* ADD-IP: Section 4.1.1 3631 * This chunk MUST be sent in an authenticated way by using 3632 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3633 * is received unauthenticated it MUST be silently discarded as 3634 * described in [I-D.ietf-tsvwg-sctp-auth]. 3635 */ 3636 if (!net->sctp.addip_noauth && !chunk->auth) 3637 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 3638 3639 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3640 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t))) 3641 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3642 commands); 3643 3644 hdr = (sctp_addiphdr_t *)chunk->skb->data; 3645 serial = ntohl(hdr->serial); 3646 3647 /* Verify the ASCONF chunk before processing it. */ 3648 if (!sctp_verify_asconf(asoc, chunk, true, &err_param)) 3649 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3650 (void *)err_param, commands); 3651 3652 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3653 * the endpoint stored in a new association variable 3654 * 'Peer-Serial-Number'. 3655 */ 3656 if (serial == asoc->peer.addip_serial + 1) { 3657 /* If this is the first instance of ASCONF in the packet, 3658 * we can clean our old ASCONF-ACKs. 3659 */ 3660 if (!chunk->has_asconf) 3661 sctp_assoc_clean_asconf_ack_cache(asoc); 3662 3663 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3664 * expected, process the ASCONF as described below and after 3665 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3666 * the response packet and cache a copy of it (in the event it 3667 * later needs to be retransmitted). 3668 * 3669 * Essentially, do V1-V5. 3670 */ 3671 asconf_ack = sctp_process_asconf((struct sctp_association *) 3672 asoc, chunk); 3673 if (!asconf_ack) 3674 return SCTP_DISPOSITION_NOMEM; 3675 } else if (serial < asoc->peer.addip_serial + 1) { 3676 /* ADDIP 5.2 E2) 3677 * If the value found in the Sequence Number is less than the 3678 * ('Peer- Sequence-Number' + 1), simply skip to the next 3679 * ASCONF, and include in the outbound response packet 3680 * any previously cached ASCONF-ACK response that was 3681 * sent and saved that matches the Sequence Number of the 3682 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3683 * Chunk exists. This will occur when an older ASCONF 3684 * arrives out of order. In such a case, the receiver 3685 * should skip the ASCONF Chunk and not include ASCONF-ACK 3686 * Chunk for that chunk. 3687 */ 3688 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3689 if (!asconf_ack) 3690 return SCTP_DISPOSITION_DISCARD; 3691 3692 /* Reset the transport so that we select the correct one 3693 * this time around. This is to make sure that we don't 3694 * accidentally use a stale transport that's been removed. 3695 */ 3696 asconf_ack->transport = NULL; 3697 } else { 3698 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3699 * it must be either a stale packet or from an attacker. 3700 */ 3701 return SCTP_DISPOSITION_DISCARD; 3702 } 3703 3704 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3705 * containing the ASCONF-ACK Chunks MUST be the source address of 3706 * the SCTP packet that held the ASCONF Chunks. 3707 * 3708 * To do this properly, we'll set the destination address of the chunk 3709 * and at the transmit time, will try look up the transport to use. 3710 * Since ASCONFs may be bundled, the correct transport may not be 3711 * created until we process the entire packet, thus this workaround. 3712 */ 3713 asconf_ack->dest = chunk->source; 3714 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3715 if (asoc->new_transport) { 3716 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands); 3717 ((struct sctp_association *)asoc)->new_transport = NULL; 3718 } 3719 3720 return SCTP_DISPOSITION_CONSUME; 3721 } 3722 3723 /* 3724 * ADDIP Section 4.3 General rules for address manipulation 3725 * When building TLV parameters for the ASCONF Chunk that will add or 3726 * delete IP addresses the D0 to D13 rules should be applied: 3727 */ 3728 sctp_disposition_t sctp_sf_do_asconf_ack(struct net *net, 3729 const struct sctp_endpoint *ep, 3730 const struct sctp_association *asoc, 3731 const sctp_subtype_t type, void *arg, 3732 sctp_cmd_seq_t *commands) 3733 { 3734 struct sctp_chunk *asconf_ack = arg; 3735 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3736 struct sctp_chunk *abort; 3737 struct sctp_paramhdr *err_param = NULL; 3738 sctp_addiphdr_t *addip_hdr; 3739 __u32 sent_serial, rcvd_serial; 3740 3741 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3742 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3743 SCTP_NULL()); 3744 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3745 } 3746 3747 /* ADD-IP, Section 4.1.2: 3748 * This chunk MUST be sent in an authenticated way by using 3749 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3750 * is received unauthenticated it MUST be silently discarded as 3751 * described in [I-D.ietf-tsvwg-sctp-auth]. 3752 */ 3753 if (!net->sctp.addip_noauth && !asconf_ack->auth) 3754 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 3755 3756 /* Make sure that the ADDIP chunk has a valid length. */ 3757 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t))) 3758 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3759 commands); 3760 3761 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data; 3762 rcvd_serial = ntohl(addip_hdr->serial); 3763 3764 /* Verify the ASCONF-ACK chunk before processing it. */ 3765 if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param)) 3766 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3767 (void *)err_param, commands); 3768 3769 if (last_asconf) { 3770 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr; 3771 sent_serial = ntohl(addip_hdr->serial); 3772 } else { 3773 sent_serial = asoc->addip_serial - 1; 3774 } 3775 3776 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3777 * equal to the next serial number to be used but no ASCONF chunk is 3778 * outstanding the endpoint MUST ABORT the association. Note that a 3779 * sequence number is greater than if it is no more than 2^^31-1 3780 * larger than the current sequence number (using serial arithmetic). 3781 */ 3782 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3783 !(asoc->addip_last_asconf)) { 3784 abort = sctp_make_abort(asoc, asconf_ack, 3785 sizeof(sctp_errhdr_t)); 3786 if (abort) { 3787 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 3788 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3789 SCTP_CHUNK(abort)); 3790 } 3791 /* We are going to ABORT, so we might as well stop 3792 * processing the rest of the chunks in the packet. 3793 */ 3794 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3795 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3796 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3797 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3798 SCTP_ERROR(ECONNABORTED)); 3799 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3800 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3801 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3802 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3803 return SCTP_DISPOSITION_ABORT; 3804 } 3805 3806 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 3807 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3808 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3809 3810 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 3811 asconf_ack)) { 3812 /* Successfully processed ASCONF_ACK. We can 3813 * release the next asconf if we have one. 3814 */ 3815 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_NEXT_ASCONF, 3816 SCTP_NULL()); 3817 return SCTP_DISPOSITION_CONSUME; 3818 } 3819 3820 abort = sctp_make_abort(asoc, asconf_ack, 3821 sizeof(sctp_errhdr_t)); 3822 if (abort) { 3823 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 3824 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3825 SCTP_CHUNK(abort)); 3826 } 3827 /* We are going to ABORT, so we might as well stop 3828 * processing the rest of the chunks in the packet. 3829 */ 3830 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3831 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3832 SCTP_ERROR(ECONNABORTED)); 3833 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3834 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3835 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3836 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3837 return SCTP_DISPOSITION_ABORT; 3838 } 3839 3840 return SCTP_DISPOSITION_DISCARD; 3841 } 3842 3843 /* RE-CONFIG Section 5.2 Upon reception of an RECONF Chunk. */ 3844 sctp_disposition_t sctp_sf_do_reconf(struct net *net, 3845 const struct sctp_endpoint *ep, 3846 const struct sctp_association *asoc, 3847 const sctp_subtype_t type, void *arg, 3848 sctp_cmd_seq_t *commands) 3849 { 3850 struct sctp_paramhdr *err_param = NULL; 3851 struct sctp_chunk *chunk = arg; 3852 struct sctp_reconf_chunk *hdr; 3853 union sctp_params param; 3854 3855 if (!sctp_vtag_verify(chunk, asoc)) { 3856 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3857 SCTP_NULL()); 3858 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3859 } 3860 3861 /* Make sure that the RECONF chunk has a valid length. */ 3862 if (!sctp_chunk_length_valid(chunk, sizeof(*hdr))) 3863 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3864 commands); 3865 3866 if (!sctp_verify_reconf(asoc, chunk, &err_param)) 3867 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3868 (void *)err_param, commands); 3869 3870 hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr; 3871 sctp_walk_params(param, hdr, params) { 3872 struct sctp_chunk *reply = NULL; 3873 struct sctp_ulpevent *ev = NULL; 3874 3875 if (param.p->type == SCTP_PARAM_RESET_OUT_REQUEST) 3876 reply = sctp_process_strreset_outreq( 3877 (struct sctp_association *)asoc, param, &ev); 3878 else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST) 3879 reply = sctp_process_strreset_inreq( 3880 (struct sctp_association *)asoc, param, &ev); 3881 else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST) 3882 reply = sctp_process_strreset_tsnreq( 3883 (struct sctp_association *)asoc, param, &ev); 3884 else if (param.p->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS) 3885 reply = sctp_process_strreset_addstrm_out( 3886 (struct sctp_association *)asoc, param, &ev); 3887 else if (param.p->type == SCTP_PARAM_RESET_ADD_IN_STREAMS) 3888 reply = sctp_process_strreset_addstrm_in( 3889 (struct sctp_association *)asoc, param, &ev); 3890 else if (param.p->type == SCTP_PARAM_RESET_RESPONSE) 3891 reply = sctp_process_strreset_resp( 3892 (struct sctp_association *)asoc, param, &ev); 3893 3894 if (ev) 3895 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 3896 SCTP_ULPEVENT(ev)); 3897 3898 if (reply) 3899 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3900 SCTP_CHUNK(reply)); 3901 } 3902 3903 return SCTP_DISPOSITION_CONSUME; 3904 } 3905 3906 /* 3907 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 3908 * 3909 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 3910 * its cumulative TSN point to the value carried in the FORWARD TSN 3911 * chunk, and then MUST further advance its cumulative TSN point locally 3912 * if possible. 3913 * After the above processing, the data receiver MUST stop reporting any 3914 * missing TSNs earlier than or equal to the new cumulative TSN point. 3915 * 3916 * Verification Tag: 8.5 Verification Tag [Normal verification] 3917 * 3918 * The return value is the disposition of the chunk. 3919 */ 3920 sctp_disposition_t sctp_sf_eat_fwd_tsn(struct net *net, 3921 const struct sctp_endpoint *ep, 3922 const struct sctp_association *asoc, 3923 const sctp_subtype_t type, 3924 void *arg, 3925 sctp_cmd_seq_t *commands) 3926 { 3927 struct sctp_chunk *chunk = arg; 3928 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3929 struct sctp_fwdtsn_skip *skip; 3930 __u16 len; 3931 __u32 tsn; 3932 3933 if (!sctp_vtag_verify(chunk, asoc)) { 3934 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3935 SCTP_NULL()); 3936 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3937 } 3938 3939 if (!asoc->peer.prsctp_capable) 3940 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 3941 3942 /* Make sure that the FORWARD_TSN chunk has valid length. */ 3943 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3944 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3945 commands); 3946 3947 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3948 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3949 len = ntohs(chunk->chunk_hdr->length); 3950 len -= sizeof(struct sctp_chunkhdr); 3951 skb_pull(chunk->skb, len); 3952 3953 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3954 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 3955 3956 /* The TSN is too high--silently discard the chunk and count on it 3957 * getting retransmitted later. 3958 */ 3959 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3960 goto discard_noforce; 3961 3962 /* Silently discard the chunk if stream-id is not valid */ 3963 sctp_walk_fwdtsn(skip, chunk) { 3964 if (ntohs(skip->stream) >= asoc->stream.incnt) 3965 goto discard_noforce; 3966 } 3967 3968 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3969 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3970 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3971 SCTP_CHUNK(chunk)); 3972 3973 /* Count this as receiving DATA. */ 3974 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 3975 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3976 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3977 } 3978 3979 /* FIXME: For now send a SACK, but DATA processing may 3980 * send another. 3981 */ 3982 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 3983 3984 return SCTP_DISPOSITION_CONSUME; 3985 3986 discard_noforce: 3987 return SCTP_DISPOSITION_DISCARD; 3988 } 3989 3990 sctp_disposition_t sctp_sf_eat_fwd_tsn_fast( 3991 struct net *net, 3992 const struct sctp_endpoint *ep, 3993 const struct sctp_association *asoc, 3994 const sctp_subtype_t type, 3995 void *arg, 3996 sctp_cmd_seq_t *commands) 3997 { 3998 struct sctp_chunk *chunk = arg; 3999 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 4000 struct sctp_fwdtsn_skip *skip; 4001 __u16 len; 4002 __u32 tsn; 4003 4004 if (!sctp_vtag_verify(chunk, asoc)) { 4005 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4006 SCTP_NULL()); 4007 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4008 } 4009 4010 if (!asoc->peer.prsctp_capable) 4011 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4012 4013 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 4014 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 4015 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4016 commands); 4017 4018 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4019 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4020 len = ntohs(chunk->chunk_hdr->length); 4021 len -= sizeof(struct sctp_chunkhdr); 4022 skb_pull(chunk->skb, len); 4023 4024 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4025 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4026 4027 /* The TSN is too high--silently discard the chunk and count on it 4028 * getting retransmitted later. 4029 */ 4030 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4031 goto gen_shutdown; 4032 4033 /* Silently discard the chunk if stream-id is not valid */ 4034 sctp_walk_fwdtsn(skip, chunk) { 4035 if (ntohs(skip->stream) >= asoc->stream.incnt) 4036 goto gen_shutdown; 4037 } 4038 4039 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4040 if (len > sizeof(struct sctp_fwdtsn_hdr)) 4041 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4042 SCTP_CHUNK(chunk)); 4043 4044 /* Go a head and force a SACK, since we are shutting down. */ 4045 gen_shutdown: 4046 /* Implementor's Guide. 4047 * 4048 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 4049 * respond to each received packet containing one or more DATA chunk(s) 4050 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 4051 */ 4052 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 4053 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 4054 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4055 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4056 4057 return SCTP_DISPOSITION_CONSUME; 4058 } 4059 4060 /* 4061 * SCTP-AUTH Section 6.3 Receiving authenticated chukns 4062 * 4063 * The receiver MUST use the HMAC algorithm indicated in the HMAC 4064 * Identifier field. If this algorithm was not specified by the 4065 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 4066 * during association setup, the AUTH chunk and all chunks after it MUST 4067 * be discarded and an ERROR chunk SHOULD be sent with the error cause 4068 * defined in Section 4.1. 4069 * 4070 * If an endpoint with no shared key receives a Shared Key Identifier 4071 * other than 0, it MUST silently discard all authenticated chunks. If 4072 * the endpoint has at least one endpoint pair shared key for the peer, 4073 * it MUST use the key specified by the Shared Key Identifier if a 4074 * key has been configured for that Shared Key Identifier. If no 4075 * endpoint pair shared key has been configured for that Shared Key 4076 * Identifier, all authenticated chunks MUST be silently discarded. 4077 * 4078 * Verification Tag: 8.5 Verification Tag [Normal verification] 4079 * 4080 * The return value is the disposition of the chunk. 4081 */ 4082 static sctp_ierror_t sctp_sf_authenticate(struct net *net, 4083 const struct sctp_endpoint *ep, 4084 const struct sctp_association *asoc, 4085 const sctp_subtype_t type, 4086 struct sctp_chunk *chunk) 4087 { 4088 struct sctp_authhdr *auth_hdr; 4089 struct sctp_hmac *hmac; 4090 unsigned int sig_len; 4091 __u16 key_id; 4092 __u8 *save_digest; 4093 __u8 *digest; 4094 4095 /* Pull in the auth header, so we can do some more verification */ 4096 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4097 chunk->subh.auth_hdr = auth_hdr; 4098 skb_pull(chunk->skb, sizeof(struct sctp_authhdr)); 4099 4100 /* Make sure that we support the HMAC algorithm from the auth 4101 * chunk. 4102 */ 4103 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 4104 return SCTP_IERROR_AUTH_BAD_HMAC; 4105 4106 /* Make sure that the provided shared key identifier has been 4107 * configured 4108 */ 4109 key_id = ntohs(auth_hdr->shkey_id); 4110 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id)) 4111 return SCTP_IERROR_AUTH_BAD_KEYID; 4112 4113 4114 /* Make sure that the length of the signature matches what 4115 * we expect. 4116 */ 4117 sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t); 4118 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 4119 if (sig_len != hmac->hmac_len) 4120 return SCTP_IERROR_PROTO_VIOLATION; 4121 4122 /* Now that we've done validation checks, we can compute and 4123 * verify the hmac. The steps involved are: 4124 * 1. Save the digest from the chunk. 4125 * 2. Zero out the digest in the chunk. 4126 * 3. Compute the new digest 4127 * 4. Compare saved and new digests. 4128 */ 4129 digest = auth_hdr->hmac; 4130 skb_pull(chunk->skb, sig_len); 4131 4132 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 4133 if (!save_digest) 4134 goto nomem; 4135 4136 memset(digest, 0, sig_len); 4137 4138 sctp_auth_calculate_hmac(asoc, chunk->skb, 4139 (struct sctp_auth_chunk *)chunk->chunk_hdr, 4140 GFP_ATOMIC); 4141 4142 /* Discard the packet if the digests do not match */ 4143 if (memcmp(save_digest, digest, sig_len)) { 4144 kfree(save_digest); 4145 return SCTP_IERROR_BAD_SIG; 4146 } 4147 4148 kfree(save_digest); 4149 chunk->auth = 1; 4150 4151 return SCTP_IERROR_NO_ERROR; 4152 nomem: 4153 return SCTP_IERROR_NOMEM; 4154 } 4155 4156 sctp_disposition_t sctp_sf_eat_auth(struct net *net, 4157 const struct sctp_endpoint *ep, 4158 const struct sctp_association *asoc, 4159 const sctp_subtype_t type, 4160 void *arg, 4161 sctp_cmd_seq_t *commands) 4162 { 4163 struct sctp_authhdr *auth_hdr; 4164 struct sctp_chunk *chunk = arg; 4165 struct sctp_chunk *err_chunk; 4166 sctp_ierror_t error; 4167 4168 /* Make sure that the peer has AUTH capable */ 4169 if (!asoc->peer.auth_capable) 4170 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4171 4172 if (!sctp_vtag_verify(chunk, asoc)) { 4173 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4174 SCTP_NULL()); 4175 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4176 } 4177 4178 /* Make sure that the AUTH chunk has valid length. */ 4179 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 4180 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4181 commands); 4182 4183 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4184 error = sctp_sf_authenticate(net, ep, asoc, type, chunk); 4185 switch (error) { 4186 case SCTP_IERROR_AUTH_BAD_HMAC: 4187 /* Generate the ERROR chunk and discard the rest 4188 * of the packet 4189 */ 4190 err_chunk = sctp_make_op_error(asoc, chunk, 4191 SCTP_ERROR_UNSUP_HMAC, 4192 &auth_hdr->hmac_id, 4193 sizeof(__u16), 0); 4194 if (err_chunk) { 4195 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4196 SCTP_CHUNK(err_chunk)); 4197 } 4198 /* Fall Through */ 4199 case SCTP_IERROR_AUTH_BAD_KEYID: 4200 case SCTP_IERROR_BAD_SIG: 4201 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4202 4203 case SCTP_IERROR_PROTO_VIOLATION: 4204 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4205 commands); 4206 4207 case SCTP_IERROR_NOMEM: 4208 return SCTP_DISPOSITION_NOMEM; 4209 4210 default: /* Prevent gcc warnings */ 4211 break; 4212 } 4213 4214 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4215 struct sctp_ulpevent *ev; 4216 4217 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4218 SCTP_AUTH_NEWKEY, GFP_ATOMIC); 4219 4220 if (!ev) 4221 return -ENOMEM; 4222 4223 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4224 SCTP_ULPEVENT(ev)); 4225 } 4226 4227 return SCTP_DISPOSITION_CONSUME; 4228 } 4229 4230 /* 4231 * Process an unknown chunk. 4232 * 4233 * Section: 3.2. Also, 2.1 in the implementor's guide. 4234 * 4235 * Chunk Types are encoded such that the highest-order two bits specify 4236 * the action that must be taken if the processing endpoint does not 4237 * recognize the Chunk Type. 4238 * 4239 * 00 - Stop processing this SCTP packet and discard it, do not process 4240 * any further chunks within it. 4241 * 4242 * 01 - Stop processing this SCTP packet and discard it, do not process 4243 * any further chunks within it, and report the unrecognized 4244 * chunk in an 'Unrecognized Chunk Type'. 4245 * 4246 * 10 - Skip this chunk and continue processing. 4247 * 4248 * 11 - Skip this chunk and continue processing, but report in an ERROR 4249 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4250 * 4251 * The return value is the disposition of the chunk. 4252 */ 4253 sctp_disposition_t sctp_sf_unk_chunk(struct net *net, 4254 const struct sctp_endpoint *ep, 4255 const struct sctp_association *asoc, 4256 const sctp_subtype_t type, 4257 void *arg, 4258 sctp_cmd_seq_t *commands) 4259 { 4260 struct sctp_chunk *unk_chunk = arg; 4261 struct sctp_chunk *err_chunk; 4262 struct sctp_chunkhdr *hdr; 4263 4264 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk); 4265 4266 if (!sctp_vtag_verify(unk_chunk, asoc)) 4267 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4268 4269 /* Make sure that the chunk has a valid length. 4270 * Since we don't know the chunk type, we use a general 4271 * chunkhdr structure to make a comparison. 4272 */ 4273 if (!sctp_chunk_length_valid(unk_chunk, sizeof(*hdr))) 4274 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4275 commands); 4276 4277 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4278 case SCTP_CID_ACTION_DISCARD: 4279 /* Discard the packet. */ 4280 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4281 case SCTP_CID_ACTION_DISCARD_ERR: 4282 /* Generate an ERROR chunk as response. */ 4283 hdr = unk_chunk->chunk_hdr; 4284 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4285 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4286 SCTP_PAD4(ntohs(hdr->length)), 4287 0); 4288 if (err_chunk) { 4289 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4290 SCTP_CHUNK(err_chunk)); 4291 } 4292 4293 /* Discard the packet. */ 4294 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4295 return SCTP_DISPOSITION_CONSUME; 4296 case SCTP_CID_ACTION_SKIP: 4297 /* Skip the chunk. */ 4298 return SCTP_DISPOSITION_DISCARD; 4299 case SCTP_CID_ACTION_SKIP_ERR: 4300 /* Generate an ERROR chunk as response. */ 4301 hdr = unk_chunk->chunk_hdr; 4302 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4303 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4304 SCTP_PAD4(ntohs(hdr->length)), 4305 0); 4306 if (err_chunk) { 4307 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4308 SCTP_CHUNK(err_chunk)); 4309 } 4310 /* Skip the chunk. */ 4311 return SCTP_DISPOSITION_CONSUME; 4312 default: 4313 break; 4314 } 4315 4316 return SCTP_DISPOSITION_DISCARD; 4317 } 4318 4319 /* 4320 * Discard the chunk. 4321 * 4322 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4323 * [Too numerous to mention...] 4324 * Verification Tag: No verification needed. 4325 * Inputs 4326 * (endpoint, asoc, chunk) 4327 * 4328 * Outputs 4329 * (asoc, reply_msg, msg_up, timers, counters) 4330 * 4331 * The return value is the disposition of the chunk. 4332 */ 4333 sctp_disposition_t sctp_sf_discard_chunk(struct net *net, 4334 const struct sctp_endpoint *ep, 4335 const struct sctp_association *asoc, 4336 const sctp_subtype_t type, 4337 void *arg, 4338 sctp_cmd_seq_t *commands) 4339 { 4340 struct sctp_chunk *chunk = arg; 4341 4342 /* Make sure that the chunk has a valid length. 4343 * Since we don't know the chunk type, we use a general 4344 * chunkhdr structure to make a comparison. 4345 */ 4346 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4347 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4348 commands); 4349 4350 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk); 4351 4352 return SCTP_DISPOSITION_DISCARD; 4353 } 4354 4355 /* 4356 * Discard the whole packet. 4357 * 4358 * Section: 8.4 2) 4359 * 4360 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4361 * silently discard the OOTB packet and take no further action. 4362 * 4363 * Verification Tag: No verification necessary 4364 * 4365 * Inputs 4366 * (endpoint, asoc, chunk) 4367 * 4368 * Outputs 4369 * (asoc, reply_msg, msg_up, timers, counters) 4370 * 4371 * The return value is the disposition of the chunk. 4372 */ 4373 sctp_disposition_t sctp_sf_pdiscard(struct net *net, 4374 const struct sctp_endpoint *ep, 4375 const struct sctp_association *asoc, 4376 const sctp_subtype_t type, 4377 void *arg, 4378 sctp_cmd_seq_t *commands) 4379 { 4380 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); 4381 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4382 4383 return SCTP_DISPOSITION_CONSUME; 4384 } 4385 4386 4387 /* 4388 * The other end is violating protocol. 4389 * 4390 * Section: Not specified 4391 * Verification Tag: Not specified 4392 * Inputs 4393 * (endpoint, asoc, chunk) 4394 * 4395 * Outputs 4396 * (asoc, reply_msg, msg_up, timers, counters) 4397 * 4398 * We simply tag the chunk as a violation. The state machine will log 4399 * the violation and continue. 4400 */ 4401 sctp_disposition_t sctp_sf_violation(struct net *net, 4402 const struct sctp_endpoint *ep, 4403 const struct sctp_association *asoc, 4404 const sctp_subtype_t type, 4405 void *arg, 4406 sctp_cmd_seq_t *commands) 4407 { 4408 struct sctp_chunk *chunk = arg; 4409 4410 /* Make sure that the chunk has a valid length. */ 4411 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4412 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4413 commands); 4414 4415 return SCTP_DISPOSITION_VIOLATION; 4416 } 4417 4418 /* 4419 * Common function to handle a protocol violation. 4420 */ 4421 static sctp_disposition_t sctp_sf_abort_violation( 4422 struct net *net, 4423 const struct sctp_endpoint *ep, 4424 const struct sctp_association *asoc, 4425 void *arg, 4426 sctp_cmd_seq_t *commands, 4427 const __u8 *payload, 4428 const size_t paylen) 4429 { 4430 struct sctp_packet *packet = NULL; 4431 struct sctp_chunk *chunk = arg; 4432 struct sctp_chunk *abort = NULL; 4433 4434 /* SCTP-AUTH, Section 6.3: 4435 * It should be noted that if the receiver wants to tear 4436 * down an association in an authenticated way only, the 4437 * handling of malformed packets should not result in 4438 * tearing down the association. 4439 * 4440 * This means that if we only want to abort associations 4441 * in an authenticated way (i.e AUTH+ABORT), then we 4442 * can't destroy this association just because the packet 4443 * was malformed. 4444 */ 4445 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4446 goto discard; 4447 4448 /* Make the abort chunk. */ 4449 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4450 if (!abort) 4451 goto nomem; 4452 4453 if (asoc) { 4454 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4455 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4456 !asoc->peer.i.init_tag) { 4457 sctp_initack_chunk_t *initack; 4458 4459 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 4460 if (!sctp_chunk_length_valid(chunk, 4461 sizeof(sctp_initack_chunk_t))) 4462 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4463 else { 4464 unsigned int inittag; 4465 4466 inittag = ntohl(initack->init_hdr.init_tag); 4467 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4468 SCTP_U32(inittag)); 4469 } 4470 } 4471 4472 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4473 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4474 4475 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4476 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4477 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4478 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4479 SCTP_ERROR(ECONNREFUSED)); 4480 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4481 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4482 } else { 4483 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4484 SCTP_ERROR(ECONNABORTED)); 4485 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4486 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4487 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4488 } 4489 } else { 4490 packet = sctp_ootb_pkt_new(net, asoc, chunk); 4491 4492 if (!packet) 4493 goto nomem_pkt; 4494 4495 if (sctp_test_T_bit(abort)) 4496 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4497 4498 abort->skb->sk = ep->base.sk; 4499 4500 sctp_packet_append_chunk(packet, abort); 4501 4502 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4503 SCTP_PACKET(packet)); 4504 4505 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4506 } 4507 4508 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4509 4510 discard: 4511 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4512 return SCTP_DISPOSITION_ABORT; 4513 4514 nomem_pkt: 4515 sctp_chunk_free(abort); 4516 nomem: 4517 return SCTP_DISPOSITION_NOMEM; 4518 } 4519 4520 /* 4521 * Handle a protocol violation when the chunk length is invalid. 4522 * "Invalid" length is identified as smaller than the minimal length a 4523 * given chunk can be. For example, a SACK chunk has invalid length 4524 * if its length is set to be smaller than the size of sctp_sack_chunk_t. 4525 * 4526 * We inform the other end by sending an ABORT with a Protocol Violation 4527 * error code. 4528 * 4529 * Section: Not specified 4530 * Verification Tag: Nothing to do 4531 * Inputs 4532 * (endpoint, asoc, chunk) 4533 * 4534 * Outputs 4535 * (reply_msg, msg_up, counters) 4536 * 4537 * Generate an ABORT chunk and terminate the association. 4538 */ 4539 static sctp_disposition_t sctp_sf_violation_chunklen( 4540 struct net *net, 4541 const struct sctp_endpoint *ep, 4542 const struct sctp_association *asoc, 4543 const sctp_subtype_t type, 4544 void *arg, 4545 sctp_cmd_seq_t *commands) 4546 { 4547 static const char err_str[] = "The following chunk had invalid length:"; 4548 4549 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4550 sizeof(err_str)); 4551 } 4552 4553 /* 4554 * Handle a protocol violation when the parameter length is invalid. 4555 * If the length is smaller than the minimum length of a given parameter, 4556 * or accumulated length in multi parameters exceeds the end of the chunk, 4557 * the length is considered as invalid. 4558 */ 4559 static sctp_disposition_t sctp_sf_violation_paramlen( 4560 struct net *net, 4561 const struct sctp_endpoint *ep, 4562 const struct sctp_association *asoc, 4563 const sctp_subtype_t type, 4564 void *arg, void *ext, 4565 sctp_cmd_seq_t *commands) 4566 { 4567 struct sctp_chunk *chunk = arg; 4568 struct sctp_paramhdr *param = ext; 4569 struct sctp_chunk *abort = NULL; 4570 4571 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4572 goto discard; 4573 4574 /* Make the abort chunk. */ 4575 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4576 if (!abort) 4577 goto nomem; 4578 4579 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4580 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4581 4582 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4583 SCTP_ERROR(ECONNABORTED)); 4584 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4585 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4586 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4587 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4588 4589 discard: 4590 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4591 return SCTP_DISPOSITION_ABORT; 4592 nomem: 4593 return SCTP_DISPOSITION_NOMEM; 4594 } 4595 4596 /* Handle a protocol violation when the peer trying to advance the 4597 * cumulative tsn ack to a point beyond the max tsn currently sent. 4598 * 4599 * We inform the other end by sending an ABORT with a Protocol Violation 4600 * error code. 4601 */ 4602 static sctp_disposition_t sctp_sf_violation_ctsn( 4603 struct net *net, 4604 const struct sctp_endpoint *ep, 4605 const struct sctp_association *asoc, 4606 const sctp_subtype_t type, 4607 void *arg, 4608 sctp_cmd_seq_t *commands) 4609 { 4610 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:"; 4611 4612 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4613 sizeof(err_str)); 4614 } 4615 4616 /* Handle protocol violation of an invalid chunk bundling. For example, 4617 * when we have an association and we receive bundled INIT-ACK, or 4618 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle" 4619 * statement from the specs. Additionally, there might be an attacker 4620 * on the path and we may not want to continue this communication. 4621 */ 4622 static sctp_disposition_t sctp_sf_violation_chunk( 4623 struct net *net, 4624 const struct sctp_endpoint *ep, 4625 const struct sctp_association *asoc, 4626 const sctp_subtype_t type, 4627 void *arg, 4628 sctp_cmd_seq_t *commands) 4629 { 4630 static const char err_str[] = "The following chunk violates protocol:"; 4631 4632 if (!asoc) 4633 return sctp_sf_violation(net, ep, asoc, type, arg, commands); 4634 4635 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4636 sizeof(err_str)); 4637 } 4638 /*************************************************************************** 4639 * These are the state functions for handling primitive (Section 10) events. 4640 ***************************************************************************/ 4641 /* 4642 * sctp_sf_do_prm_asoc 4643 * 4644 * Section: 10.1 ULP-to-SCTP 4645 * B) Associate 4646 * 4647 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4648 * outbound stream count) 4649 * -> association id [,destination transport addr list] [,outbound stream 4650 * count] 4651 * 4652 * This primitive allows the upper layer to initiate an association to a 4653 * specific peer endpoint. 4654 * 4655 * The peer endpoint shall be specified by one of the transport addresses 4656 * which defines the endpoint (see Section 1.4). If the local SCTP 4657 * instance has not been initialized, the ASSOCIATE is considered an 4658 * error. 4659 * [This is not relevant for the kernel implementation since we do all 4660 * initialization at boot time. It we hadn't initialized we wouldn't 4661 * get anywhere near this code.] 4662 * 4663 * An association id, which is a local handle to the SCTP association, 4664 * will be returned on successful establishment of the association. If 4665 * SCTP is not able to open an SCTP association with the peer endpoint, 4666 * an error is returned. 4667 * [In the kernel implementation, the struct sctp_association needs to 4668 * be created BEFORE causing this primitive to run.] 4669 * 4670 * Other association parameters may be returned, including the 4671 * complete destination transport addresses of the peer as well as the 4672 * outbound stream count of the local endpoint. One of the transport 4673 * address from the returned destination addresses will be selected by 4674 * the local endpoint as default primary path for sending SCTP packets 4675 * to this peer. The returned "destination transport addr list" can 4676 * be used by the ULP to change the default primary path or to force 4677 * sending a packet to a specific transport address. [All of this 4678 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4679 * function.] 4680 * 4681 * Mandatory attributes: 4682 * 4683 * o local SCTP instance name - obtained from the INITIALIZE operation. 4684 * [This is the argument asoc.] 4685 * o destination transport addr - specified as one of the transport 4686 * addresses of the peer endpoint with which the association is to be 4687 * established. 4688 * [This is asoc->peer.active_path.] 4689 * o outbound stream count - the number of outbound streams the ULP 4690 * would like to open towards this peer endpoint. 4691 * [BUG: This is not currently implemented.] 4692 * Optional attributes: 4693 * 4694 * None. 4695 * 4696 * The return value is a disposition. 4697 */ 4698 sctp_disposition_t sctp_sf_do_prm_asoc(struct net *net, 4699 const struct sctp_endpoint *ep, 4700 const struct sctp_association *asoc, 4701 const sctp_subtype_t type, 4702 void *arg, 4703 sctp_cmd_seq_t *commands) 4704 { 4705 struct sctp_chunk *repl; 4706 struct sctp_association *my_asoc; 4707 4708 /* The comment below says that we enter COOKIE-WAIT AFTER 4709 * sending the INIT, but that doesn't actually work in our 4710 * implementation... 4711 */ 4712 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4713 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4714 4715 /* RFC 2960 5.1 Normal Establishment of an Association 4716 * 4717 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4718 * must provide its Verification Tag (Tag_A) in the Initiate 4719 * Tag field. Tag_A SHOULD be a random number in the range of 4720 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4721 */ 4722 4723 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 4724 if (!repl) 4725 goto nomem; 4726 4727 /* Choose transport for INIT. */ 4728 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4729 SCTP_CHUNK(repl)); 4730 4731 /* Cast away the const modifier, as we want to just 4732 * rerun it through as a sideffect. 4733 */ 4734 my_asoc = (struct sctp_association *)asoc; 4735 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 4736 4737 /* After sending the INIT, "A" starts the T1-init timer and 4738 * enters the COOKIE-WAIT state. 4739 */ 4740 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4741 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4742 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4743 return SCTP_DISPOSITION_CONSUME; 4744 4745 nomem: 4746 return SCTP_DISPOSITION_NOMEM; 4747 } 4748 4749 /* 4750 * Process the SEND primitive. 4751 * 4752 * Section: 10.1 ULP-to-SCTP 4753 * E) Send 4754 * 4755 * Format: SEND(association id, buffer address, byte count [,context] 4756 * [,stream id] [,life time] [,destination transport address] 4757 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 4758 * -> result 4759 * 4760 * This is the main method to send user data via SCTP. 4761 * 4762 * Mandatory attributes: 4763 * 4764 * o association id - local handle to the SCTP association 4765 * 4766 * o buffer address - the location where the user message to be 4767 * transmitted is stored; 4768 * 4769 * o byte count - The size of the user data in number of bytes; 4770 * 4771 * Optional attributes: 4772 * 4773 * o context - an optional 32 bit integer that will be carried in the 4774 * sending failure notification to the ULP if the transportation of 4775 * this User Message fails. 4776 * 4777 * o stream id - to indicate which stream to send the data on. If not 4778 * specified, stream 0 will be used. 4779 * 4780 * o life time - specifies the life time of the user data. The user data 4781 * will not be sent by SCTP after the life time expires. This 4782 * parameter can be used to avoid efforts to transmit stale 4783 * user messages. SCTP notifies the ULP if the data cannot be 4784 * initiated to transport (i.e. sent to the destination via SCTP's 4785 * send primitive) within the life time variable. However, the 4786 * user data will be transmitted if SCTP has attempted to transmit a 4787 * chunk before the life time expired. 4788 * 4789 * o destination transport address - specified as one of the destination 4790 * transport addresses of the peer endpoint to which this packet 4791 * should be sent. Whenever possible, SCTP should use this destination 4792 * transport address for sending the packets, instead of the current 4793 * primary path. 4794 * 4795 * o unorder flag - this flag, if present, indicates that the user 4796 * would like the data delivered in an unordered fashion to the peer 4797 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 4798 * message). 4799 * 4800 * o no-bundle flag - instructs SCTP not to bundle this user data with 4801 * other outbound DATA chunks. SCTP MAY still bundle even when 4802 * this flag is present, when faced with network congestion. 4803 * 4804 * o payload protocol-id - A 32 bit unsigned integer that is to be 4805 * passed to the peer indicating the type of payload protocol data 4806 * being transmitted. This value is passed as opaque data by SCTP. 4807 * 4808 * The return value is the disposition. 4809 */ 4810 sctp_disposition_t sctp_sf_do_prm_send(struct net *net, 4811 const struct sctp_endpoint *ep, 4812 const struct sctp_association *asoc, 4813 const sctp_subtype_t type, 4814 void *arg, 4815 sctp_cmd_seq_t *commands) 4816 { 4817 struct sctp_datamsg *msg = arg; 4818 4819 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 4820 return SCTP_DISPOSITION_CONSUME; 4821 } 4822 4823 /* 4824 * Process the SHUTDOWN primitive. 4825 * 4826 * Section: 10.1: 4827 * C) Shutdown 4828 * 4829 * Format: SHUTDOWN(association id) 4830 * -> result 4831 * 4832 * Gracefully closes an association. Any locally queued user data 4833 * will be delivered to the peer. The association will be terminated only 4834 * after the peer acknowledges all the SCTP packets sent. A success code 4835 * will be returned on successful termination of the association. If 4836 * attempting to terminate the association results in a failure, an error 4837 * code shall be returned. 4838 * 4839 * Mandatory attributes: 4840 * 4841 * o association id - local handle to the SCTP association 4842 * 4843 * Optional attributes: 4844 * 4845 * None. 4846 * 4847 * The return value is the disposition. 4848 */ 4849 sctp_disposition_t sctp_sf_do_9_2_prm_shutdown( 4850 struct net *net, 4851 const struct sctp_endpoint *ep, 4852 const struct sctp_association *asoc, 4853 const sctp_subtype_t type, 4854 void *arg, 4855 sctp_cmd_seq_t *commands) 4856 { 4857 int disposition; 4858 4859 /* From 9.2 Shutdown of an Association 4860 * Upon receipt of the SHUTDOWN primitive from its upper 4861 * layer, the endpoint enters SHUTDOWN-PENDING state and 4862 * remains there until all outstanding data has been 4863 * acknowledged by its peer. The endpoint accepts no new data 4864 * from its upper layer, but retransmits data to the far end 4865 * if necessary to fill gaps. 4866 */ 4867 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4868 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 4869 4870 disposition = SCTP_DISPOSITION_CONSUME; 4871 if (sctp_outq_is_empty(&asoc->outqueue)) { 4872 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 4873 arg, commands); 4874 } 4875 return disposition; 4876 } 4877 4878 /* 4879 * Process the ABORT primitive. 4880 * 4881 * Section: 10.1: 4882 * C) Abort 4883 * 4884 * Format: Abort(association id [, cause code]) 4885 * -> result 4886 * 4887 * Ungracefully closes an association. Any locally queued user data 4888 * will be discarded and an ABORT chunk is sent to the peer. A success code 4889 * will be returned on successful abortion of the association. If 4890 * attempting to abort the association results in a failure, an error 4891 * code shall be returned. 4892 * 4893 * Mandatory attributes: 4894 * 4895 * o association id - local handle to the SCTP association 4896 * 4897 * Optional attributes: 4898 * 4899 * o cause code - reason of the abort to be passed to the peer 4900 * 4901 * None. 4902 * 4903 * The return value is the disposition. 4904 */ 4905 sctp_disposition_t sctp_sf_do_9_1_prm_abort( 4906 struct net *net, 4907 const struct sctp_endpoint *ep, 4908 const struct sctp_association *asoc, 4909 const sctp_subtype_t type, 4910 void *arg, 4911 sctp_cmd_seq_t *commands) 4912 { 4913 /* From 9.1 Abort of an Association 4914 * Upon receipt of the ABORT primitive from its upper 4915 * layer, the endpoint enters CLOSED state and 4916 * discard all outstanding data has been 4917 * acknowledged by its peer. The endpoint accepts no new data 4918 * from its upper layer, but retransmits data to the far end 4919 * if necessary to fill gaps. 4920 */ 4921 struct sctp_chunk *abort = arg; 4922 4923 if (abort) 4924 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4925 4926 /* Even if we can't send the ABORT due to low memory delete the 4927 * TCB. This is a departure from our typical NOMEM handling. 4928 */ 4929 4930 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4931 SCTP_ERROR(ECONNABORTED)); 4932 /* Delete the established association. */ 4933 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4934 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4935 4936 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4937 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4938 4939 return SCTP_DISPOSITION_ABORT; 4940 } 4941 4942 /* We tried an illegal operation on an association which is closed. */ 4943 sctp_disposition_t sctp_sf_error_closed(struct net *net, 4944 const struct sctp_endpoint *ep, 4945 const struct sctp_association *asoc, 4946 const sctp_subtype_t type, 4947 void *arg, 4948 sctp_cmd_seq_t *commands) 4949 { 4950 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 4951 return SCTP_DISPOSITION_CONSUME; 4952 } 4953 4954 /* We tried an illegal operation on an association which is shutting 4955 * down. 4956 */ 4957 sctp_disposition_t sctp_sf_error_shutdown(struct net *net, 4958 const struct sctp_endpoint *ep, 4959 const struct sctp_association *asoc, 4960 const sctp_subtype_t type, 4961 void *arg, 4962 sctp_cmd_seq_t *commands) 4963 { 4964 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 4965 SCTP_ERROR(-ESHUTDOWN)); 4966 return SCTP_DISPOSITION_CONSUME; 4967 } 4968 4969 /* 4970 * sctp_cookie_wait_prm_shutdown 4971 * 4972 * Section: 4 Note: 2 4973 * Verification Tag: 4974 * Inputs 4975 * (endpoint, asoc) 4976 * 4977 * The RFC does not explicitly address this issue, but is the route through the 4978 * state table when someone issues a shutdown while in COOKIE_WAIT state. 4979 * 4980 * Outputs 4981 * (timers) 4982 */ 4983 sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown( 4984 struct net *net, 4985 const struct sctp_endpoint *ep, 4986 const struct sctp_association *asoc, 4987 const sctp_subtype_t type, 4988 void *arg, 4989 sctp_cmd_seq_t *commands) 4990 { 4991 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4992 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4993 4994 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4995 SCTP_STATE(SCTP_STATE_CLOSED)); 4996 4997 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 4998 4999 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 5000 5001 return SCTP_DISPOSITION_DELETE_TCB; 5002 } 5003 5004 /* 5005 * sctp_cookie_echoed_prm_shutdown 5006 * 5007 * Section: 4 Note: 2 5008 * Verification Tag: 5009 * Inputs 5010 * (endpoint, asoc) 5011 * 5012 * The RFC does not explcitly address this issue, but is the route through the 5013 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 5014 * 5015 * Outputs 5016 * (timers) 5017 */ 5018 sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown( 5019 struct net *net, 5020 const struct sctp_endpoint *ep, 5021 const struct sctp_association *asoc, 5022 const sctp_subtype_t type, 5023 void *arg, sctp_cmd_seq_t *commands) 5024 { 5025 /* There is a single T1 timer, so we should be able to use 5026 * common function with the COOKIE-WAIT state. 5027 */ 5028 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands); 5029 } 5030 5031 /* 5032 * sctp_sf_cookie_wait_prm_abort 5033 * 5034 * Section: 4 Note: 2 5035 * Verification Tag: 5036 * Inputs 5037 * (endpoint, asoc) 5038 * 5039 * The RFC does not explicitly address this issue, but is the route through the 5040 * state table when someone issues an abort while in COOKIE_WAIT state. 5041 * 5042 * Outputs 5043 * (timers) 5044 */ 5045 sctp_disposition_t sctp_sf_cookie_wait_prm_abort( 5046 struct net *net, 5047 const struct sctp_endpoint *ep, 5048 const struct sctp_association *asoc, 5049 const sctp_subtype_t type, 5050 void *arg, 5051 sctp_cmd_seq_t *commands) 5052 { 5053 struct sctp_chunk *abort = arg; 5054 5055 /* Stop T1-init timer */ 5056 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5057 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5058 5059 if (abort) 5060 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5061 5062 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5063 SCTP_STATE(SCTP_STATE_CLOSED)); 5064 5065 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5066 5067 /* Even if we can't send the ABORT due to low memory delete the 5068 * TCB. This is a departure from our typical NOMEM handling. 5069 */ 5070 5071 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5072 SCTP_ERROR(ECONNREFUSED)); 5073 /* Delete the established association. */ 5074 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5075 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5076 5077 return SCTP_DISPOSITION_ABORT; 5078 } 5079 5080 /* 5081 * sctp_sf_cookie_echoed_prm_abort 5082 * 5083 * Section: 4 Note: 3 5084 * Verification Tag: 5085 * Inputs 5086 * (endpoint, asoc) 5087 * 5088 * The RFC does not explcitly address this issue, but is the route through the 5089 * state table when someone issues an abort while in COOKIE_ECHOED state. 5090 * 5091 * Outputs 5092 * (timers) 5093 */ 5094 sctp_disposition_t sctp_sf_cookie_echoed_prm_abort( 5095 struct net *net, 5096 const struct sctp_endpoint *ep, 5097 const struct sctp_association *asoc, 5098 const sctp_subtype_t type, 5099 void *arg, 5100 sctp_cmd_seq_t *commands) 5101 { 5102 /* There is a single T1 timer, so we should be able to use 5103 * common function with the COOKIE-WAIT state. 5104 */ 5105 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands); 5106 } 5107 5108 /* 5109 * sctp_sf_shutdown_pending_prm_abort 5110 * 5111 * Inputs 5112 * (endpoint, asoc) 5113 * 5114 * The RFC does not explicitly address this issue, but is the route through the 5115 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 5116 * 5117 * Outputs 5118 * (timers) 5119 */ 5120 sctp_disposition_t sctp_sf_shutdown_pending_prm_abort( 5121 struct net *net, 5122 const struct sctp_endpoint *ep, 5123 const struct sctp_association *asoc, 5124 const sctp_subtype_t type, 5125 void *arg, 5126 sctp_cmd_seq_t *commands) 5127 { 5128 /* Stop the T5-shutdown guard timer. */ 5129 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5130 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5131 5132 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5133 } 5134 5135 /* 5136 * sctp_sf_shutdown_sent_prm_abort 5137 * 5138 * Inputs 5139 * (endpoint, asoc) 5140 * 5141 * The RFC does not explicitly address this issue, but is the route through the 5142 * state table when someone issues an abort while in SHUTDOWN-SENT state. 5143 * 5144 * Outputs 5145 * (timers) 5146 */ 5147 sctp_disposition_t sctp_sf_shutdown_sent_prm_abort( 5148 struct net *net, 5149 const struct sctp_endpoint *ep, 5150 const struct sctp_association *asoc, 5151 const sctp_subtype_t type, 5152 void *arg, 5153 sctp_cmd_seq_t *commands) 5154 { 5155 /* Stop the T2-shutdown timer. */ 5156 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5157 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5158 5159 /* Stop the T5-shutdown guard timer. */ 5160 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5161 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5162 5163 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5164 } 5165 5166 /* 5167 * sctp_sf_cookie_echoed_prm_abort 5168 * 5169 * Inputs 5170 * (endpoint, asoc) 5171 * 5172 * The RFC does not explcitly address this issue, but is the route through the 5173 * state table when someone issues an abort while in COOKIE_ECHOED state. 5174 * 5175 * Outputs 5176 * (timers) 5177 */ 5178 sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort( 5179 struct net *net, 5180 const struct sctp_endpoint *ep, 5181 const struct sctp_association *asoc, 5182 const sctp_subtype_t type, 5183 void *arg, 5184 sctp_cmd_seq_t *commands) 5185 { 5186 /* The same T2 timer, so we should be able to use 5187 * common function with the SHUTDOWN-SENT state. 5188 */ 5189 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands); 5190 } 5191 5192 /* 5193 * Process the REQUESTHEARTBEAT primitive 5194 * 5195 * 10.1 ULP-to-SCTP 5196 * J) Request Heartbeat 5197 * 5198 * Format: REQUESTHEARTBEAT(association id, destination transport address) 5199 * 5200 * -> result 5201 * 5202 * Instructs the local endpoint to perform a HeartBeat on the specified 5203 * destination transport address of the given association. The returned 5204 * result should indicate whether the transmission of the HEARTBEAT 5205 * chunk to the destination address is successful. 5206 * 5207 * Mandatory attributes: 5208 * 5209 * o association id - local handle to the SCTP association 5210 * 5211 * o destination transport address - the transport address of the 5212 * association on which a heartbeat should be issued. 5213 */ 5214 sctp_disposition_t sctp_sf_do_prm_requestheartbeat( 5215 struct net *net, 5216 const struct sctp_endpoint *ep, 5217 const struct sctp_association *asoc, 5218 const sctp_subtype_t type, 5219 void *arg, 5220 sctp_cmd_seq_t *commands) 5221 { 5222 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 5223 (struct sctp_transport *)arg, commands)) 5224 return SCTP_DISPOSITION_NOMEM; 5225 5226 /* 5227 * RFC 2960 (bis), section 8.3 5228 * 5229 * D) Request an on-demand HEARTBEAT on a specific destination 5230 * transport address of a given association. 5231 * 5232 * The endpoint should increment the respective error counter of 5233 * the destination transport address each time a HEARTBEAT is sent 5234 * to that address and not acknowledged within one RTO. 5235 * 5236 */ 5237 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5238 SCTP_TRANSPORT(arg)); 5239 return SCTP_DISPOSITION_CONSUME; 5240 } 5241 5242 /* 5243 * ADDIP Section 4.1 ASCONF Chunk Procedures 5244 * When an endpoint has an ASCONF signaled change to be sent to the 5245 * remote endpoint it should do A1 to A9 5246 */ 5247 sctp_disposition_t sctp_sf_do_prm_asconf(struct net *net, 5248 const struct sctp_endpoint *ep, 5249 const struct sctp_association *asoc, 5250 const sctp_subtype_t type, 5251 void *arg, 5252 sctp_cmd_seq_t *commands) 5253 { 5254 struct sctp_chunk *chunk = arg; 5255 5256 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5257 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5258 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5259 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5260 return SCTP_DISPOSITION_CONSUME; 5261 } 5262 5263 /* RE-CONFIG Section 5.1 RECONF Chunk Procedures */ 5264 sctp_disposition_t sctp_sf_do_prm_reconf(struct net *net, 5265 const struct sctp_endpoint *ep, 5266 const struct sctp_association *asoc, 5267 const sctp_subtype_t type, 5268 void *arg, sctp_cmd_seq_t *commands) 5269 { 5270 struct sctp_chunk *chunk = arg; 5271 5272 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5273 return SCTP_DISPOSITION_CONSUME; 5274 } 5275 5276 /* 5277 * Ignore the primitive event 5278 * 5279 * The return value is the disposition of the primitive. 5280 */ 5281 sctp_disposition_t sctp_sf_ignore_primitive( 5282 struct net *net, 5283 const struct sctp_endpoint *ep, 5284 const struct sctp_association *asoc, 5285 const sctp_subtype_t type, 5286 void *arg, 5287 sctp_cmd_seq_t *commands) 5288 { 5289 pr_debug("%s: primitive type:%d is ignored\n", __func__, 5290 type.primitive); 5291 5292 return SCTP_DISPOSITION_DISCARD; 5293 } 5294 5295 /*************************************************************************** 5296 * These are the state functions for the OTHER events. 5297 ***************************************************************************/ 5298 5299 /* 5300 * When the SCTP stack has no more user data to send or retransmit, this 5301 * notification is given to the user. Also, at the time when a user app 5302 * subscribes to this event, if there is no data to be sent or 5303 * retransmit, the stack will immediately send up this notification. 5304 */ 5305 sctp_disposition_t sctp_sf_do_no_pending_tsn( 5306 struct net *net, 5307 const struct sctp_endpoint *ep, 5308 const struct sctp_association *asoc, 5309 const sctp_subtype_t type, 5310 void *arg, 5311 sctp_cmd_seq_t *commands) 5312 { 5313 struct sctp_ulpevent *event; 5314 5315 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC); 5316 if (!event) 5317 return SCTP_DISPOSITION_NOMEM; 5318 5319 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event)); 5320 5321 return SCTP_DISPOSITION_CONSUME; 5322 } 5323 5324 /* 5325 * Start the shutdown negotiation. 5326 * 5327 * From Section 9.2: 5328 * Once all its outstanding data has been acknowledged, the endpoint 5329 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5330 * TSN Ack field the last sequential TSN it has received from the peer. 5331 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5332 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5333 * with the updated last sequential TSN received from its peer. 5334 * 5335 * The return value is the disposition. 5336 */ 5337 sctp_disposition_t sctp_sf_do_9_2_start_shutdown( 5338 struct net *net, 5339 const struct sctp_endpoint *ep, 5340 const struct sctp_association *asoc, 5341 const sctp_subtype_t type, 5342 void *arg, 5343 sctp_cmd_seq_t *commands) 5344 { 5345 struct sctp_chunk *reply; 5346 5347 /* Once all its outstanding data has been acknowledged, the 5348 * endpoint shall send a SHUTDOWN chunk to its peer including 5349 * in the Cumulative TSN Ack field the last sequential TSN it 5350 * has received from the peer. 5351 */ 5352 reply = sctp_make_shutdown(asoc, NULL); 5353 if (!reply) 5354 goto nomem; 5355 5356 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5357 * T2-shutdown timer. 5358 */ 5359 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5360 5361 /* It shall then start the T2-shutdown timer */ 5362 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5363 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5364 5365 /* RFC 4960 Section 9.2 5366 * The sender of the SHUTDOWN MAY also start an overall guard timer 5367 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5368 */ 5369 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5370 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5371 5372 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5373 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5374 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5375 5376 /* and enter the SHUTDOWN-SENT state. */ 5377 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5378 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5379 5380 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5381 * 5382 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5383 * or SHUTDOWN-ACK. 5384 */ 5385 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5386 5387 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5388 5389 return SCTP_DISPOSITION_CONSUME; 5390 5391 nomem: 5392 return SCTP_DISPOSITION_NOMEM; 5393 } 5394 5395 /* 5396 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5397 * 5398 * From Section 9.2: 5399 * 5400 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5401 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5402 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5403 * endpoint must re-send the SHUTDOWN ACK. 5404 * 5405 * The return value is the disposition. 5406 */ 5407 sctp_disposition_t sctp_sf_do_9_2_shutdown_ack( 5408 struct net *net, 5409 const struct sctp_endpoint *ep, 5410 const struct sctp_association *asoc, 5411 const sctp_subtype_t type, 5412 void *arg, 5413 sctp_cmd_seq_t *commands) 5414 { 5415 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 5416 struct sctp_chunk *reply; 5417 5418 /* There are 2 ways of getting here: 5419 * 1) called in response to a SHUTDOWN chunk 5420 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5421 * 5422 * For the case (2), the arg parameter is set to NULL. We need 5423 * to check that we have a chunk before accessing it's fields. 5424 */ 5425 if (chunk) { 5426 if (!sctp_vtag_verify(chunk, asoc)) 5427 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 5428 5429 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5430 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t))) 5431 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 5432 commands); 5433 } 5434 5435 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5436 * shall send a SHUTDOWN ACK ... 5437 */ 5438 reply = sctp_make_shutdown_ack(asoc, chunk); 5439 if (!reply) 5440 goto nomem; 5441 5442 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5443 * the T2-shutdown timer. 5444 */ 5445 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5446 5447 /* and start/restart a T2-shutdown timer of its own, */ 5448 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5449 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5450 5451 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5452 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5453 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5454 5455 /* Enter the SHUTDOWN-ACK-SENT state. */ 5456 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5457 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5458 5459 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5460 * 5461 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5462 * or SHUTDOWN-ACK. 5463 */ 5464 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5465 5466 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5467 5468 return SCTP_DISPOSITION_CONSUME; 5469 5470 nomem: 5471 return SCTP_DISPOSITION_NOMEM; 5472 } 5473 5474 /* 5475 * Ignore the event defined as other 5476 * 5477 * The return value is the disposition of the event. 5478 */ 5479 sctp_disposition_t sctp_sf_ignore_other(struct net *net, 5480 const struct sctp_endpoint *ep, 5481 const struct sctp_association *asoc, 5482 const sctp_subtype_t type, 5483 void *arg, 5484 sctp_cmd_seq_t *commands) 5485 { 5486 pr_debug("%s: the event other type:%d is ignored\n", 5487 __func__, type.other); 5488 5489 return SCTP_DISPOSITION_DISCARD; 5490 } 5491 5492 /************************************************************ 5493 * These are the state functions for handling timeout events. 5494 ************************************************************/ 5495 5496 /* 5497 * RTX Timeout 5498 * 5499 * Section: 6.3.3 Handle T3-rtx Expiration 5500 * 5501 * Whenever the retransmission timer T3-rtx expires for a destination 5502 * address, do the following: 5503 * [See below] 5504 * 5505 * The return value is the disposition of the chunk. 5506 */ 5507 sctp_disposition_t sctp_sf_do_6_3_3_rtx(struct net *net, 5508 const struct sctp_endpoint *ep, 5509 const struct sctp_association *asoc, 5510 const sctp_subtype_t type, 5511 void *arg, 5512 sctp_cmd_seq_t *commands) 5513 { 5514 struct sctp_transport *transport = arg; 5515 5516 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS); 5517 5518 if (asoc->overall_error_count >= asoc->max_retrans) { 5519 if (asoc->peer.zero_window_announced && 5520 asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { 5521 /* 5522 * We are here likely because the receiver had its rwnd 5523 * closed for a while and we have not been able to 5524 * transmit the locally queued data within the maximum 5525 * retransmission attempts limit. Start the T5 5526 * shutdown guard timer to give the receiver one last 5527 * chance and some additional time to recover before 5528 * aborting. 5529 */ 5530 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE, 5531 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5532 } else { 5533 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5534 SCTP_ERROR(ETIMEDOUT)); 5535 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5536 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5537 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5538 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5539 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5540 return SCTP_DISPOSITION_DELETE_TCB; 5541 } 5542 } 5543 5544 /* E1) For the destination address for which the timer 5545 * expires, adjust its ssthresh with rules defined in Section 5546 * 7.2.3 and set the cwnd <- MTU. 5547 */ 5548 5549 /* E2) For the destination address for which the timer 5550 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5551 * maximum value discussed in rule C7 above (RTO.max) may be 5552 * used to provide an upper bound to this doubling operation. 5553 */ 5554 5555 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5556 * outstanding DATA chunks for the address for which the 5557 * T3-rtx has expired will fit into a single packet, subject 5558 * to the MTU constraint for the path corresponding to the 5559 * destination transport address to which the retransmission 5560 * is being sent (this may be different from the address for 5561 * which the timer expires [see Section 6.4]). Call this 5562 * value K. Bundle and retransmit those K DATA chunks in a 5563 * single packet to the destination endpoint. 5564 * 5565 * Note: Any DATA chunks that were sent to the address for 5566 * which the T3-rtx timer expired but did not fit in one MTU 5567 * (rule E3 above), should be marked for retransmission and 5568 * sent as soon as cwnd allows (normally when a SACK arrives). 5569 */ 5570 5571 /* Do some failure management (Section 8.2). */ 5572 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5573 5574 /* NB: Rules E4 and F1 are implicit in R1. */ 5575 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5576 5577 return SCTP_DISPOSITION_CONSUME; 5578 } 5579 5580 /* 5581 * Generate delayed SACK on timeout 5582 * 5583 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5584 * 5585 * The guidelines on delayed acknowledgement algorithm specified in 5586 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5587 * acknowledgement SHOULD be generated for at least every second packet 5588 * (not every second DATA chunk) received, and SHOULD be generated 5589 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5590 * some situations it may be beneficial for an SCTP transmitter to be 5591 * more conservative than the algorithms detailed in this document 5592 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5593 * the following algorithms allow. 5594 */ 5595 sctp_disposition_t sctp_sf_do_6_2_sack(struct net *net, 5596 const struct sctp_endpoint *ep, 5597 const struct sctp_association *asoc, 5598 const sctp_subtype_t type, 5599 void *arg, 5600 sctp_cmd_seq_t *commands) 5601 { 5602 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS); 5603 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5604 return SCTP_DISPOSITION_CONSUME; 5605 } 5606 5607 /* 5608 * sctp_sf_t1_init_timer_expire 5609 * 5610 * Section: 4 Note: 2 5611 * Verification Tag: 5612 * Inputs 5613 * (endpoint, asoc) 5614 * 5615 * RFC 2960 Section 4 Notes 5616 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5617 * and re-start the T1-init timer without changing state. This MUST 5618 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5619 * endpoint MUST abort the initialization process and report the 5620 * error to SCTP user. 5621 * 5622 * Outputs 5623 * (timers, events) 5624 * 5625 */ 5626 sctp_disposition_t sctp_sf_t1_init_timer_expire(struct net *net, 5627 const struct sctp_endpoint *ep, 5628 const struct sctp_association *asoc, 5629 const sctp_subtype_t type, 5630 void *arg, 5631 sctp_cmd_seq_t *commands) 5632 { 5633 struct sctp_chunk *repl = NULL; 5634 struct sctp_bind_addr *bp; 5635 int attempts = asoc->init_err_counter + 1; 5636 5637 pr_debug("%s: timer T1 expired (INIT)\n", __func__); 5638 5639 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS); 5640 5641 if (attempts <= asoc->max_init_attempts) { 5642 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5643 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5644 if (!repl) 5645 return SCTP_DISPOSITION_NOMEM; 5646 5647 /* Choose transport for INIT. */ 5648 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5649 SCTP_CHUNK(repl)); 5650 5651 /* Issue a sideeffect to do the needed accounting. */ 5652 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5653 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5654 5655 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5656 } else { 5657 pr_debug("%s: giving up on INIT, attempts:%d " 5658 "max_init_attempts:%d\n", __func__, attempts, 5659 asoc->max_init_attempts); 5660 5661 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5662 SCTP_ERROR(ETIMEDOUT)); 5663 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5664 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5665 return SCTP_DISPOSITION_DELETE_TCB; 5666 } 5667 5668 return SCTP_DISPOSITION_CONSUME; 5669 } 5670 5671 /* 5672 * sctp_sf_t1_cookie_timer_expire 5673 * 5674 * Section: 4 Note: 2 5675 * Verification Tag: 5676 * Inputs 5677 * (endpoint, asoc) 5678 * 5679 * RFC 2960 Section 4 Notes 5680 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5681 * COOKIE ECHO and re-start the T1-cookie timer without changing 5682 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5683 * After that, the endpoint MUST abort the initialization process and 5684 * report the error to SCTP user. 5685 * 5686 * Outputs 5687 * (timers, events) 5688 * 5689 */ 5690 sctp_disposition_t sctp_sf_t1_cookie_timer_expire(struct net *net, 5691 const struct sctp_endpoint *ep, 5692 const struct sctp_association *asoc, 5693 const sctp_subtype_t type, 5694 void *arg, 5695 sctp_cmd_seq_t *commands) 5696 { 5697 struct sctp_chunk *repl = NULL; 5698 int attempts = asoc->init_err_counter + 1; 5699 5700 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__); 5701 5702 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS); 5703 5704 if (attempts <= asoc->max_init_attempts) { 5705 repl = sctp_make_cookie_echo(asoc, NULL); 5706 if (!repl) 5707 return SCTP_DISPOSITION_NOMEM; 5708 5709 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5710 SCTP_CHUNK(repl)); 5711 /* Issue a sideeffect to do the needed accounting. */ 5712 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5713 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5714 5715 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5716 } else { 5717 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5718 SCTP_ERROR(ETIMEDOUT)); 5719 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5720 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5721 return SCTP_DISPOSITION_DELETE_TCB; 5722 } 5723 5724 return SCTP_DISPOSITION_CONSUME; 5725 } 5726 5727 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 5728 * with the updated last sequential TSN received from its peer. 5729 * 5730 * An endpoint should limit the number of retransmissions of the 5731 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 5732 * If this threshold is exceeded the endpoint should destroy the TCB and 5733 * MUST report the peer endpoint unreachable to the upper layer (and 5734 * thus the association enters the CLOSED state). The reception of any 5735 * packet from its peer (i.e. as the peer sends all of its queued DATA 5736 * chunks) should clear the endpoint's retransmission count and restart 5737 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 5738 * all of its queued DATA chunks that have not yet been sent. 5739 */ 5740 sctp_disposition_t sctp_sf_t2_timer_expire(struct net *net, 5741 const struct sctp_endpoint *ep, 5742 const struct sctp_association *asoc, 5743 const sctp_subtype_t type, 5744 void *arg, 5745 sctp_cmd_seq_t *commands) 5746 { 5747 struct sctp_chunk *reply = NULL; 5748 5749 pr_debug("%s: timer T2 expired\n", __func__); 5750 5751 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 5752 5753 ((struct sctp_association *)asoc)->shutdown_retries++; 5754 5755 if (asoc->overall_error_count >= asoc->max_retrans) { 5756 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5757 SCTP_ERROR(ETIMEDOUT)); 5758 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5759 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5760 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5761 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5762 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5763 return SCTP_DISPOSITION_DELETE_TCB; 5764 } 5765 5766 switch (asoc->state) { 5767 case SCTP_STATE_SHUTDOWN_SENT: 5768 reply = sctp_make_shutdown(asoc, NULL); 5769 break; 5770 5771 case SCTP_STATE_SHUTDOWN_ACK_SENT: 5772 reply = sctp_make_shutdown_ack(asoc, NULL); 5773 break; 5774 5775 default: 5776 BUG(); 5777 break; 5778 } 5779 5780 if (!reply) 5781 goto nomem; 5782 5783 /* Do some failure management (Section 8.2). 5784 * If we remove the transport an SHUTDOWN was last sent to, don't 5785 * do failure management. 5786 */ 5787 if (asoc->shutdown_last_sent_to) 5788 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5789 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 5790 5791 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 5792 * the T2-shutdown timer. 5793 */ 5794 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5795 5796 /* Restart the T2-shutdown timer. */ 5797 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5798 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5799 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5800 return SCTP_DISPOSITION_CONSUME; 5801 5802 nomem: 5803 return SCTP_DISPOSITION_NOMEM; 5804 } 5805 5806 /* 5807 * ADDIP Section 4.1 ASCONF CHunk Procedures 5808 * If the T4 RTO timer expires the endpoint should do B1 to B5 5809 */ 5810 sctp_disposition_t sctp_sf_t4_timer_expire( 5811 struct net *net, 5812 const struct sctp_endpoint *ep, 5813 const struct sctp_association *asoc, 5814 const sctp_subtype_t type, 5815 void *arg, 5816 sctp_cmd_seq_t *commands) 5817 { 5818 struct sctp_chunk *chunk = asoc->addip_last_asconf; 5819 struct sctp_transport *transport = chunk->transport; 5820 5821 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS); 5822 5823 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 5824 * detection on the appropriate destination address as defined in 5825 * RFC2960 [5] section 8.1 and 8.2. 5826 */ 5827 if (transport) 5828 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5829 SCTP_TRANSPORT(transport)); 5830 5831 /* Reconfig T4 timer and transport. */ 5832 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5833 5834 /* ADDIP 4.1 B2) Increment the association error counters and perform 5835 * endpoint failure detection on the association as defined in 5836 * RFC2960 [5] section 8.1 and 8.2. 5837 * association error counter is incremented in SCTP_CMD_STRIKE. 5838 */ 5839 if (asoc->overall_error_count >= asoc->max_retrans) { 5840 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5841 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5842 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5843 SCTP_ERROR(ETIMEDOUT)); 5844 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5845 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5846 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5847 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5848 return SCTP_DISPOSITION_ABORT; 5849 } 5850 5851 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 5852 * the ASCONF chunk was sent by doubling the RTO timer value. 5853 * This is done in SCTP_CMD_STRIKE. 5854 */ 5855 5856 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 5857 * choose an alternate destination address (please refer to RFC2960 5858 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 5859 * chunk, it MUST be the same (including its serial number) as the last 5860 * ASCONF sent. 5861 */ 5862 sctp_chunk_hold(asoc->addip_last_asconf); 5863 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5864 SCTP_CHUNK(asoc->addip_last_asconf)); 5865 5866 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 5867 * destination is selected, then the RTO used will be that of the new 5868 * destination address. 5869 */ 5870 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5871 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5872 5873 return SCTP_DISPOSITION_CONSUME; 5874 } 5875 5876 /* sctpimpguide-05 Section 2.12.2 5877 * The sender of the SHUTDOWN MAY also start an overall guard timer 5878 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5879 * At the expiration of this timer the sender SHOULD abort the association 5880 * by sending an ABORT chunk. 5881 */ 5882 sctp_disposition_t sctp_sf_t5_timer_expire(struct net *net, 5883 const struct sctp_endpoint *ep, 5884 const struct sctp_association *asoc, 5885 const sctp_subtype_t type, 5886 void *arg, 5887 sctp_cmd_seq_t *commands) 5888 { 5889 struct sctp_chunk *reply = NULL; 5890 5891 pr_debug("%s: timer T5 expired\n", __func__); 5892 5893 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 5894 5895 reply = sctp_make_abort(asoc, NULL, 0); 5896 if (!reply) 5897 goto nomem; 5898 5899 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5900 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5901 SCTP_ERROR(ETIMEDOUT)); 5902 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5903 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5904 5905 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5906 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5907 5908 return SCTP_DISPOSITION_DELETE_TCB; 5909 nomem: 5910 return SCTP_DISPOSITION_NOMEM; 5911 } 5912 5913 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 5914 * the association is automatically closed by starting the shutdown process. 5915 * The work that needs to be done is same as when SHUTDOWN is initiated by 5916 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 5917 */ 5918 sctp_disposition_t sctp_sf_autoclose_timer_expire( 5919 struct net *net, 5920 const struct sctp_endpoint *ep, 5921 const struct sctp_association *asoc, 5922 const sctp_subtype_t type, 5923 void *arg, 5924 sctp_cmd_seq_t *commands) 5925 { 5926 int disposition; 5927 5928 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS); 5929 5930 /* From 9.2 Shutdown of an Association 5931 * Upon receipt of the SHUTDOWN primitive from its upper 5932 * layer, the endpoint enters SHUTDOWN-PENDING state and 5933 * remains there until all outstanding data has been 5934 * acknowledged by its peer. The endpoint accepts no new data 5935 * from its upper layer, but retransmits data to the far end 5936 * if necessary to fill gaps. 5937 */ 5938 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5939 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5940 5941 disposition = SCTP_DISPOSITION_CONSUME; 5942 if (sctp_outq_is_empty(&asoc->outqueue)) { 5943 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 5944 arg, commands); 5945 } 5946 return disposition; 5947 } 5948 5949 /***************************************************************************** 5950 * These are sa state functions which could apply to all types of events. 5951 ****************************************************************************/ 5952 5953 /* 5954 * This table entry is not implemented. 5955 * 5956 * Inputs 5957 * (endpoint, asoc, chunk) 5958 * 5959 * The return value is the disposition of the chunk. 5960 */ 5961 sctp_disposition_t sctp_sf_not_impl(struct net *net, 5962 const struct sctp_endpoint *ep, 5963 const struct sctp_association *asoc, 5964 const sctp_subtype_t type, 5965 void *arg, 5966 sctp_cmd_seq_t *commands) 5967 { 5968 return SCTP_DISPOSITION_NOT_IMPL; 5969 } 5970 5971 /* 5972 * This table entry represents a bug. 5973 * 5974 * Inputs 5975 * (endpoint, asoc, chunk) 5976 * 5977 * The return value is the disposition of the chunk. 5978 */ 5979 sctp_disposition_t sctp_sf_bug(struct net *net, 5980 const struct sctp_endpoint *ep, 5981 const struct sctp_association *asoc, 5982 const sctp_subtype_t type, 5983 void *arg, 5984 sctp_cmd_seq_t *commands) 5985 { 5986 return SCTP_DISPOSITION_BUG; 5987 } 5988 5989 /* 5990 * This table entry represents the firing of a timer in the wrong state. 5991 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 5992 * when the association is in the wrong state. This event should 5993 * be ignored, so as to prevent any rearming of the timer. 5994 * 5995 * Inputs 5996 * (endpoint, asoc, chunk) 5997 * 5998 * The return value is the disposition of the chunk. 5999 */ 6000 sctp_disposition_t sctp_sf_timer_ignore(struct net *net, 6001 const struct sctp_endpoint *ep, 6002 const struct sctp_association *asoc, 6003 const sctp_subtype_t type, 6004 void *arg, 6005 sctp_cmd_seq_t *commands) 6006 { 6007 pr_debug("%s: timer %d ignored\n", __func__, type.chunk); 6008 6009 return SCTP_DISPOSITION_CONSUME; 6010 } 6011 6012 /******************************************************************** 6013 * 2nd Level Abstractions 6014 ********************************************************************/ 6015 6016 /* Pull the SACK chunk based on the SACK header. */ 6017 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 6018 { 6019 struct sctp_sackhdr *sack; 6020 unsigned int len; 6021 __u16 num_blocks; 6022 __u16 num_dup_tsns; 6023 6024 /* Protect ourselves from reading too far into 6025 * the skb from a bogus sender. 6026 */ 6027 sack = (struct sctp_sackhdr *) chunk->skb->data; 6028 6029 num_blocks = ntohs(sack->num_gap_ack_blocks); 6030 num_dup_tsns = ntohs(sack->num_dup_tsns); 6031 len = sizeof(struct sctp_sackhdr); 6032 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 6033 if (len > chunk->skb->len) 6034 return NULL; 6035 6036 skb_pull(chunk->skb, len); 6037 6038 return sack; 6039 } 6040 6041 /* Create an ABORT packet to be sent as a response, with the specified 6042 * error causes. 6043 */ 6044 static struct sctp_packet *sctp_abort_pkt_new(struct net *net, 6045 const struct sctp_endpoint *ep, 6046 const struct sctp_association *asoc, 6047 struct sctp_chunk *chunk, 6048 const void *payload, 6049 size_t paylen) 6050 { 6051 struct sctp_packet *packet; 6052 struct sctp_chunk *abort; 6053 6054 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6055 6056 if (packet) { 6057 /* Make an ABORT. 6058 * The T bit will be set if the asoc is NULL. 6059 */ 6060 abort = sctp_make_abort(asoc, chunk, paylen); 6061 if (!abort) { 6062 sctp_ootb_pkt_free(packet); 6063 return NULL; 6064 } 6065 6066 /* Reflect vtag if T-Bit is set */ 6067 if (sctp_test_T_bit(abort)) 6068 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 6069 6070 /* Add specified error causes, i.e., payload, to the 6071 * end of the chunk. 6072 */ 6073 sctp_addto_chunk(abort, paylen, payload); 6074 6075 /* Set the skb to the belonging sock for accounting. */ 6076 abort->skb->sk = ep->base.sk; 6077 6078 sctp_packet_append_chunk(packet, abort); 6079 6080 } 6081 6082 return packet; 6083 } 6084 6085 /* Allocate a packet for responding in the OOTB conditions. */ 6086 static struct sctp_packet *sctp_ootb_pkt_new(struct net *net, 6087 const struct sctp_association *asoc, 6088 const struct sctp_chunk *chunk) 6089 { 6090 struct sctp_packet *packet; 6091 struct sctp_transport *transport; 6092 __u16 sport; 6093 __u16 dport; 6094 __u32 vtag; 6095 6096 /* Get the source and destination port from the inbound packet. */ 6097 sport = ntohs(chunk->sctp_hdr->dest); 6098 dport = ntohs(chunk->sctp_hdr->source); 6099 6100 /* The V-tag is going to be the same as the inbound packet if no 6101 * association exists, otherwise, use the peer's vtag. 6102 */ 6103 if (asoc) { 6104 /* Special case the INIT-ACK as there is no peer's vtag 6105 * yet. 6106 */ 6107 switch (chunk->chunk_hdr->type) { 6108 case SCTP_CID_INIT_ACK: 6109 { 6110 sctp_initack_chunk_t *initack; 6111 6112 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 6113 vtag = ntohl(initack->init_hdr.init_tag); 6114 break; 6115 } 6116 default: 6117 vtag = asoc->peer.i.init_tag; 6118 break; 6119 } 6120 } else { 6121 /* Special case the INIT and stale COOKIE_ECHO as there is no 6122 * vtag yet. 6123 */ 6124 switch (chunk->chunk_hdr->type) { 6125 case SCTP_CID_INIT: 6126 { 6127 struct sctp_init_chunk *init; 6128 6129 init = (struct sctp_init_chunk *)chunk->chunk_hdr; 6130 vtag = ntohl(init->init_hdr.init_tag); 6131 break; 6132 } 6133 default: 6134 vtag = ntohl(chunk->sctp_hdr->vtag); 6135 break; 6136 } 6137 } 6138 6139 /* Make a transport for the bucket, Eliza... */ 6140 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC); 6141 if (!transport) 6142 goto nomem; 6143 6144 /* Cache a route for the transport with the chunk's destination as 6145 * the source address. 6146 */ 6147 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 6148 sctp_sk(net->sctp.ctl_sock)); 6149 6150 packet = &transport->packet; 6151 sctp_packet_init(packet, transport, sport, dport); 6152 sctp_packet_config(packet, vtag, 0); 6153 6154 return packet; 6155 6156 nomem: 6157 return NULL; 6158 } 6159 6160 /* Free the packet allocated earlier for responding in the OOTB condition. */ 6161 void sctp_ootb_pkt_free(struct sctp_packet *packet) 6162 { 6163 sctp_transport_free(packet->transport); 6164 } 6165 6166 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 6167 static void sctp_send_stale_cookie_err(struct net *net, 6168 const struct sctp_endpoint *ep, 6169 const struct sctp_association *asoc, 6170 const struct sctp_chunk *chunk, 6171 sctp_cmd_seq_t *commands, 6172 struct sctp_chunk *err_chunk) 6173 { 6174 struct sctp_packet *packet; 6175 6176 if (err_chunk) { 6177 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6178 if (packet) { 6179 struct sctp_signed_cookie *cookie; 6180 6181 /* Override the OOTB vtag from the cookie. */ 6182 cookie = chunk->subh.cookie_hdr; 6183 packet->vtag = cookie->c.peer_vtag; 6184 6185 /* Set the skb to the belonging sock for accounting. */ 6186 err_chunk->skb->sk = ep->base.sk; 6187 sctp_packet_append_chunk(packet, err_chunk); 6188 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 6189 SCTP_PACKET(packet)); 6190 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 6191 } else 6192 sctp_chunk_free (err_chunk); 6193 } 6194 } 6195 6196 6197 /* Process a data chunk */ 6198 static int sctp_eat_data(const struct sctp_association *asoc, 6199 struct sctp_chunk *chunk, 6200 sctp_cmd_seq_t *commands) 6201 { 6202 struct sctp_datahdr *data_hdr; 6203 struct sctp_chunk *err; 6204 size_t datalen; 6205 sctp_verb_t deliver; 6206 int tmp; 6207 __u32 tsn; 6208 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 6209 struct sock *sk = asoc->base.sk; 6210 struct net *net = sock_net(sk); 6211 u16 ssn; 6212 u16 sid; 6213 u8 ordered = 0; 6214 6215 data_hdr = (struct sctp_datahdr *)chunk->skb->data; 6216 chunk->subh.data_hdr = data_hdr; 6217 skb_pull(chunk->skb, sizeof(*data_hdr)); 6218 6219 tsn = ntohl(data_hdr->tsn); 6220 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 6221 6222 /* ASSERT: Now skb->data is really the user data. */ 6223 6224 /* Process ECN based congestion. 6225 * 6226 * Since the chunk structure is reused for all chunks within 6227 * a packet, we use ecn_ce_done to track if we've already 6228 * done CE processing for this packet. 6229 * 6230 * We need to do ECN processing even if we plan to discard the 6231 * chunk later. 6232 */ 6233 6234 if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) { 6235 struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af; 6236 chunk->ecn_ce_done = 1; 6237 6238 if (af->is_ce(sctp_gso_headskb(chunk->skb))) { 6239 /* Do real work as sideffect. */ 6240 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 6241 SCTP_U32(tsn)); 6242 } 6243 } 6244 6245 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 6246 if (tmp < 0) { 6247 /* The TSN is too high--silently discard the chunk and 6248 * count on it getting retransmitted later. 6249 */ 6250 if (chunk->asoc) 6251 chunk->asoc->stats.outofseqtsns++; 6252 return SCTP_IERROR_HIGH_TSN; 6253 } else if (tmp > 0) { 6254 /* This is a duplicate. Record it. */ 6255 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 6256 return SCTP_IERROR_DUP_TSN; 6257 } 6258 6259 /* This is a new TSN. */ 6260 6261 /* Discard if there is no room in the receive window. 6262 * Actually, allow a little bit of overflow (up to a MTU). 6263 */ 6264 datalen = ntohs(chunk->chunk_hdr->length); 6265 datalen -= sizeof(struct sctp_data_chunk); 6266 6267 deliver = SCTP_CMD_CHUNK_ULP; 6268 6269 /* Think about partial delivery. */ 6270 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 6271 6272 /* Even if we don't accept this chunk there is 6273 * memory pressure. 6274 */ 6275 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 6276 } 6277 6278 /* Spill over rwnd a little bit. Note: While allowed, this spill over 6279 * seems a bit troublesome in that frag_point varies based on 6280 * PMTU. In cases, such as loopback, this might be a rather 6281 * large spill over. 6282 */ 6283 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 6284 (datalen > asoc->rwnd + asoc->frag_point))) { 6285 6286 /* If this is the next TSN, consider reneging to make 6287 * room. Note: Playing nice with a confused sender. A 6288 * malicious sender can still eat up all our buffer 6289 * space and in the future we may want to detect and 6290 * do more drastic reneging. 6291 */ 6292 if (sctp_tsnmap_has_gap(map) && 6293 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6294 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn); 6295 deliver = SCTP_CMD_RENEGE; 6296 } else { 6297 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n", 6298 __func__, tsn, datalen, asoc->rwnd); 6299 6300 return SCTP_IERROR_IGNORE_TSN; 6301 } 6302 } 6303 6304 /* 6305 * Also try to renege to limit our memory usage in the event that 6306 * we are under memory pressure 6307 * If we can't renege, don't worry about it, the sk_rmem_schedule 6308 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 6309 * memory usage too much 6310 */ 6311 if (*sk->sk_prot_creator->memory_pressure) { 6312 if (sctp_tsnmap_has_gap(map) && 6313 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6314 pr_debug("%s: under pressure, reneging for tsn:%u\n", 6315 __func__, tsn); 6316 deliver = SCTP_CMD_RENEGE; 6317 } 6318 } 6319 6320 /* 6321 * Section 3.3.10.9 No User Data (9) 6322 * 6323 * Cause of error 6324 * --------------- 6325 * No User Data: This error cause is returned to the originator of a 6326 * DATA chunk if a received DATA chunk has no user data. 6327 */ 6328 if (unlikely(0 == datalen)) { 6329 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6330 if (err) { 6331 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6332 SCTP_CHUNK(err)); 6333 } 6334 /* We are going to ABORT, so we might as well stop 6335 * processing the rest of the chunks in the packet. 6336 */ 6337 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 6338 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6339 SCTP_ERROR(ECONNABORTED)); 6340 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6341 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6342 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6343 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6344 return SCTP_IERROR_NO_DATA; 6345 } 6346 6347 chunk->data_accepted = 1; 6348 6349 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6350 * if we renege and the chunk arrives again. 6351 */ 6352 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) { 6353 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS); 6354 if (chunk->asoc) 6355 chunk->asoc->stats.iuodchunks++; 6356 } else { 6357 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS); 6358 if (chunk->asoc) 6359 chunk->asoc->stats.iodchunks++; 6360 ordered = 1; 6361 } 6362 6363 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6364 * 6365 * If an endpoint receive a DATA chunk with an invalid stream 6366 * identifier, it shall acknowledge the reception of the DATA chunk 6367 * following the normal procedure, immediately send an ERROR chunk 6368 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6369 * and discard the DATA chunk. 6370 */ 6371 sid = ntohs(data_hdr->stream); 6372 if (sid >= asoc->stream.incnt) { 6373 /* Mark tsn as received even though we drop it */ 6374 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6375 6376 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6377 &data_hdr->stream, 6378 sizeof(data_hdr->stream), 6379 sizeof(u16)); 6380 if (err) 6381 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6382 SCTP_CHUNK(err)); 6383 return SCTP_IERROR_BAD_STREAM; 6384 } 6385 6386 /* Check to see if the SSN is possible for this TSN. 6387 * The biggest gap we can record is 4K wide. Since SSNs wrap 6388 * at an unsigned short, there is no way that an SSN can 6389 * wrap and for a valid TSN. We can simply check if the current 6390 * SSN is smaller then the next expected one. If it is, it wrapped 6391 * and is invalid. 6392 */ 6393 ssn = ntohs(data_hdr->ssn); 6394 if (ordered && SSN_lt(ssn, sctp_ssn_peek(&asoc->stream, in, sid))) 6395 return SCTP_IERROR_PROTO_VIOLATION; 6396 6397 /* Send the data up to the user. Note: Schedule the 6398 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6399 * chunk needs the updated rwnd. 6400 */ 6401 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6402 6403 return SCTP_IERROR_NO_ERROR; 6404 } 6405